diff --git a/app/components/create_log_actions_component.html.erb b/app/components/create_log_actions_component.html.erb
index 1b6bd8aca..5a90587ed 100644
--- a/app/components/create_log_actions_component.html.erb
+++ b/app/components/create_log_actions_component.html.erb
@@ -3,7 +3,7 @@
     <% if create_button_href.present? %>
       <%= govuk_button_to create_button_copy, create_button_href, class: "govuk-!-margin-right-6" %>
     <% end %>
-    <% if upload_button_href.present? %>
+    <% if upload_button_href.present? && !user.support? %>
       <%= govuk_button_link_to upload_button_copy, upload_button_href, secondary: true %>
     <% end %>
   </div>
diff --git a/app/controllers/bulk_upload_lettings_logs_controller.rb b/app/controllers/bulk_upload_lettings_logs_controller.rb
index 465bbc5f6..a8ad14f9e 100644
--- a/app/controllers/bulk_upload_lettings_logs_controller.rb
+++ b/app/controllers/bulk_upload_lettings_logs_controller.rb
@@ -4,9 +4,9 @@ class BulkUploadLettingsLogsController < ApplicationController
 
   def start
     if have_choice_of_year?
-      redirect_to bulk_upload_lettings_log_path(id: "year")
+      redirect_to bulk_upload_lettings_log_path(id: "year", form: { organisation_id: params[:organisation_id] }.compact)
     else
-      redirect_to bulk_upload_lettings_log_path(id: "prepare-your-file", form: { year: current_year })
+      redirect_to bulk_upload_lettings_log_path(id: "prepare-your-file", form: { year: current_year, organisation_id: params[:organisation_id] }.compact)
     end
   end
 
@@ -60,6 +60,6 @@ private
   end
 
   def form_params
-    params.fetch(:form, {}).permit(:year, :needstype, :file)
+    params.fetch(:form, {}).permit(:year, :needstype, :file, :organisation_id)
   end
 end
diff --git a/app/controllers/bulk_upload_sales_logs_controller.rb b/app/controllers/bulk_upload_sales_logs_controller.rb
index 56bd1d4de..2fd312d10 100644
--- a/app/controllers/bulk_upload_sales_logs_controller.rb
+++ b/app/controllers/bulk_upload_sales_logs_controller.rb
@@ -4,9 +4,9 @@ class BulkUploadSalesLogsController < ApplicationController
 
   def start
     if have_choice_of_year?
-      redirect_to bulk_upload_sales_log_path(id: "year")
+      redirect_to bulk_upload_sales_log_path(id: "year", form: { organisation_id: params[:organisation_id] }.compact)
     else
-      redirect_to bulk_upload_sales_log_path(id: "prepare-your-file", form: { year: current_year })
+      redirect_to bulk_upload_sales_log_path(id: "prepare-your-file", form: { year: current_year, organisation_id: params[:organisation_id] }.compact)
     end
   end
 
@@ -58,6 +58,6 @@ private
   end
 
   def form_params
-    params.fetch(:form, {}).permit(:year, :file)
+    params.fetch(:form, {}).permit(:year, :file, :organisation_id)
   end
 end
diff --git a/app/models/forms/bulk_upload_lettings/checking_file.rb b/app/models/forms/bulk_upload_lettings/checking_file.rb
index 8cd9ee696..3b43cb269 100644
--- a/app/models/forms/bulk_upload_lettings/checking_file.rb
+++ b/app/models/forms/bulk_upload_lettings/checking_file.rb
@@ -6,13 +6,18 @@ module Forms
       include Rails.application.routes.url_helpers
 
       attribute :year, :integer
+      attribute :organisation_id, :integer
 
       def view_path
         "bulk_upload_lettings_logs/forms/checking_file"
       end
 
       def back_path
-        bulk_upload_lettings_log_path(id: "start")
+        if organisation_id.present?
+          lettings_logs_organisation_path(organisation_id)
+        else
+          bulk_upload_lettings_log_path(id: "start")
+        end
       end
 
       def year_combo
diff --git a/app/models/forms/bulk_upload_lettings/guidance.rb b/app/models/forms/bulk_upload_lettings/guidance.rb
index b6cf5bf74..24bc531f2 100644
--- a/app/models/forms/bulk_upload_lettings/guidance.rb
+++ b/app/models/forms/bulk_upload_lettings/guidance.rb
@@ -7,6 +7,7 @@ module Forms
 
       attribute :year, :integer
       attribute :referrer
+      attribute :organisation_id, :integer
 
       def view_path
         "bulk_upload_shared/guidance"
@@ -15,7 +16,7 @@ module Forms
       def back_path
         case referrer
         when "prepare-your-file"
-          bulk_upload_lettings_log_path(id: "prepare-your-file", form: { year: })
+          bulk_upload_lettings_log_path(id: "prepare-your-file", form: { year:, organisation_id: }.compact)
         when "home"
           root_path
         else
diff --git a/app/models/forms/bulk_upload_lettings/needstype.rb b/app/models/forms/bulk_upload_lettings/needstype.rb
index 0cadd647c..32ed0acf3 100644
--- a/app/models/forms/bulk_upload_lettings/needstype.rb
+++ b/app/models/forms/bulk_upload_lettings/needstype.rb
@@ -7,6 +7,7 @@ module Forms
 
       attribute :needstype, :integer
       attribute :year, :integer
+      attribute :organisation_id, :integer
 
       validates :needstype, presence: true
 
@@ -19,11 +20,11 @@ module Forms
       end
 
       def back_path
-        bulk_upload_lettings_log_path(id: "prepare-your-file", form: { year:, needstype: })
+        bulk_upload_lettings_log_path(id: "prepare-your-file", form: { year:, needstype:, organisation_id: }.compact)
       end
 
       def next_path
-        bulk_upload_lettings_log_path(id: "upload-your-file", form: { year:, needstype: })
+        bulk_upload_lettings_log_path(id: "upload-your-file", form: { year:, needstype:, organisation_id: }.compact)
       end
 
       def year_combo
diff --git a/app/models/forms/bulk_upload_lettings/prepare_your_file.rb b/app/models/forms/bulk_upload_lettings/prepare_your_file.rb
index b5069d908..159436ce1 100644
--- a/app/models/forms/bulk_upload_lettings/prepare_your_file.rb
+++ b/app/models/forms/bulk_upload_lettings/prepare_your_file.rb
@@ -7,6 +7,7 @@ module Forms
 
       attribute :year, :integer
       attribute :needstype, :integer
+      attribute :organisation_id, :integer
 
       def view_path
         case year
@@ -19,15 +20,16 @@ module Forms
 
       def back_path
         if have_choice_of_year?
-          Rails.application.routes.url_helpers.bulk_upload_lettings_log_path(id: "year", form: { year: })
+          Rails.application.routes.url_helpers.bulk_upload_lettings_log_path(id: "year", form: { year:, organisation_id: }.compact)
+        elsif organisation_id.present?
+          lettings_logs_organisation_path(organisation_id)
         else
           Rails.application.routes.url_helpers.lettings_logs_path
         end
       end
 
       def next_path
-        page_id = year == 2022 ? "needstype" : "upload-your-file"
-        bulk_upload_lettings_log_path(id: page_id, form: { year:, needstype: })
+        bulk_upload_lettings_log_path(id: "upload-your-file", form: { year:, needstype:, organisation_id: }.compact)
       end
 
       def legacy_template_path
diff --git a/app/models/forms/bulk_upload_lettings/upload_your_file.rb b/app/models/forms/bulk_upload_lettings/upload_your_file.rb
index 9ccec7622..954c6e6e6 100644
--- a/app/models/forms/bulk_upload_lettings/upload_your_file.rb
+++ b/app/models/forms/bulk_upload_lettings/upload_your_file.rb
@@ -11,6 +11,7 @@ module Forms
       attribute :needstype, :integer
       attribute :file
       attribute :current_user
+      attribute :organisation_id, :integer
 
       validates :file, presence: true
       validate :validate_file_is_csv
@@ -20,8 +21,7 @@ module Forms
       end
 
       def back_path
-        page_id = year == 2022 ? "needstype" : "prepare-your-file"
-        bulk_upload_lettings_log_path(id: page_id, form: { year:, needstype: })
+        bulk_upload_lettings_log_path(id: "prepare-your-file", form: { year:, needstype:, organisation_id: }.compact)
       end
 
       def year_combo
@@ -29,7 +29,7 @@ module Forms
       end
 
       def next_path
-        bulk_upload_lettings_log_path(id: "checking-file", form: { year: })
+        bulk_upload_lettings_log_path(id: "checking-file", form: { year:, organisation_id: }.compact)
       end
 
       def save!
@@ -39,6 +39,7 @@ module Forms
           year:,
           needstype:,
           filename: file.original_filename,
+          organisation_id: (organisation_id if current_user.support?) || current_user.organisation_id,
         )
 
         storage_service.write_file(bulk_upload.identifier, File.read(file.path))
diff --git a/app/models/forms/bulk_upload_lettings/year.rb b/app/models/forms/bulk_upload_lettings/year.rb
index e199559fa..396b91a79 100644
--- a/app/models/forms/bulk_upload_lettings/year.rb
+++ b/app/models/forms/bulk_upload_lettings/year.rb
@@ -6,6 +6,7 @@ module Forms
       include Rails.application.routes.url_helpers
 
       attribute :year, :integer
+      attribute :organisation_id, :integer
 
       validates :year, presence: true
 
@@ -20,11 +21,15 @@ module Forms
       end
 
       def back_path
-        lettings_logs_path
+        if organisation_id.present?
+          lettings_logs_organisation_path(organisation_id)
+        else
+          lettings_logs_path
+        end
       end
 
       def next_path
-        bulk_upload_lettings_log_path(id: "prepare-your-file", form: { year: })
+        bulk_upload_lettings_log_path(id: "prepare-your-file", form: { year:, organisation_id: }.compact)
       end
 
       def save!
diff --git a/app/models/forms/bulk_upload_sales/checking_file.rb b/app/models/forms/bulk_upload_sales/checking_file.rb
index a37be3ccb..243d64070 100644
--- a/app/models/forms/bulk_upload_sales/checking_file.rb
+++ b/app/models/forms/bulk_upload_sales/checking_file.rb
@@ -6,13 +6,18 @@ module Forms
       include Rails.application.routes.url_helpers
 
       attribute :year, :integer
+      attribute :organisation_id, :integer
 
       def view_path
         "bulk_upload_sales_logs/forms/checking_file"
       end
 
       def back_path
-        bulk_upload_sales_log_path(id: "start")
+        if organisation_id.present?
+          sales_logs_organisation_path(organisation_id)
+        else
+          bulk_upload_sales_log_path(id: "start")
+        end
       end
 
       def year_combo
diff --git a/app/models/forms/bulk_upload_sales/guidance.rb b/app/models/forms/bulk_upload_sales/guidance.rb
index 28ca6c3b5..ef792a3e4 100644
--- a/app/models/forms/bulk_upload_sales/guidance.rb
+++ b/app/models/forms/bulk_upload_sales/guidance.rb
@@ -7,6 +7,7 @@ module Forms
 
       attribute :year, :integer
       attribute :referrer
+      attribute :organisation_id, :integer
 
       def view_path
         "bulk_upload_shared/guidance"
@@ -15,7 +16,7 @@ module Forms
       def back_path
         case referrer
         when "prepare-your-file"
-          bulk_upload_sales_log_path(id: "prepare-your-file", form: { year: })
+          bulk_upload_sales_log_path(id: "prepare-your-file", form: { year:, organisation_id: }.compact)
         when "home"
           root_path
         else
diff --git a/app/models/forms/bulk_upload_sales/prepare_your_file.rb b/app/models/forms/bulk_upload_sales/prepare_your_file.rb
index 387f6239f..4bf0797a8 100644
--- a/app/models/forms/bulk_upload_sales/prepare_your_file.rb
+++ b/app/models/forms/bulk_upload_sales/prepare_your_file.rb
@@ -6,6 +6,7 @@ module Forms
       include Rails.application.routes.url_helpers
 
       attribute :year, :integer
+      attribute :organisation_id, :integer
 
       def view_path
         case year
@@ -18,14 +19,16 @@ module Forms
 
       def back_path
         if have_choice_of_year?
-          Rails.application.routes.url_helpers.bulk_upload_sales_log_path(id: "year", form: { year: })
+          Rails.application.routes.url_helpers.bulk_upload_sales_log_path(id: "year", form: { year: }.compact)
+        elsif organisation_id.present?
+          sales_logs_organisation_path(organisation_id)
         else
           Rails.application.routes.url_helpers.sales_logs_path
         end
       end
 
       def next_path
-        bulk_upload_sales_log_path(id: "upload-your-file", form: { year: })
+        bulk_upload_sales_log_path(id: "upload-your-file", form: { year:, organisation_id: }.compact)
       end
 
       def legacy_template_path
diff --git a/app/models/forms/bulk_upload_sales/upload_your_file.rb b/app/models/forms/bulk_upload_sales/upload_your_file.rb
index de650c831..5a0114caf 100644
--- a/app/models/forms/bulk_upload_sales/upload_your_file.rb
+++ b/app/models/forms/bulk_upload_sales/upload_your_file.rb
@@ -10,6 +10,7 @@ module Forms
       attribute :year, :integer
       attribute :file
       attribute :current_user
+      attribute :organisation_id, :integer
 
       validates :file, presence: true
       validate :validate_file_is_csv
@@ -19,7 +20,7 @@ module Forms
       end
 
       def back_path
-        bulk_upload_sales_log_path(id: "prepare-your-file", form: { year: })
+        bulk_upload_sales_log_path(id: "prepare-your-file", form: { year:, organisation_id: }.compact)
       end
 
       def year_combo
@@ -27,7 +28,7 @@ module Forms
       end
 
       def next_path
-        bulk_upload_sales_log_path(id: "checking-file", form: { year: })
+        bulk_upload_sales_log_path(id: "checking-file", form: { year:, organisation_id: }.compact)
       end
 
       def save!
@@ -36,6 +37,7 @@ module Forms
           log_type: BulkUpload.log_types[:sales],
           year:,
           filename: file.original_filename,
+          organisation_id: (organisation_id if current_user.support?) || current_user.organisation_id,
         )
 
         storage_service.write_file(bulk_upload.identifier, File.read(file.path))
diff --git a/app/models/forms/bulk_upload_sales/year.rb b/app/models/forms/bulk_upload_sales/year.rb
index 85959c4e5..1de8dec04 100644
--- a/app/models/forms/bulk_upload_sales/year.rb
+++ b/app/models/forms/bulk_upload_sales/year.rb
@@ -6,6 +6,7 @@ module Forms
       include Rails.application.routes.url_helpers
 
       attribute :year, :integer
+      attribute :organisation_id, :integer
 
       validates :year, presence: true
 
@@ -20,11 +21,15 @@ module Forms
       end
 
       def back_path
-        sales_logs_path
+        if organisation_id.present?
+          sales_logs_organisation_path(organisation_id)
+        else
+          sales_logs_path
+        end
       end
 
       def next_path
-        bulk_upload_sales_log_path(id: "prepare-your-file", form: { year: })
+        bulk_upload_sales_log_path(id: "prepare-your-file", form: { year:, organisation_id: }.compact)
       end
 
       def save!
diff --git a/app/services/bulk_upload/lettings/year2024/row_parser.rb b/app/services/bulk_upload/lettings/year2024/row_parser.rb
index 8fc913055..dc0b2dca3 100644
--- a/app/services/bulk_upload/lettings/year2024/row_parser.rb
+++ b/app/services/bulk_upload/lettings/year2024/row_parser.rb
@@ -432,6 +432,7 @@ class BulkUpload::Lettings::Year2024::RowParser
 
   validate :validate_assigned_to_exists, on: :after_log
   validate :validate_assigned_to_related, on: :after_log
+  validate :validate_assigned_to_when_support, on: :after_log
   validate :validate_all_charges_given, on: :after_log, if: proc { is_carehome.zero? }
 
   validate :validate_address_option_found, on: :after_log, unless: -> { supported_housing? }
@@ -582,6 +583,12 @@ private
     end
   end
 
+  def validate_assigned_to_when_support
+    if field_3.blank? && bulk_upload.user.support?
+      errors.add(:field_3, category: :setup, message: I18n.t("validations.not_answered", question: "what is the CORE username of the account this letting log should be assigned to?"))
+    end
+  end
+
   def validate_assigned_to_related
     return unless assigned_to
     return if assigned_to.organisation == owning_organisation || assigned_to.organisation == managing_organisation
@@ -891,12 +898,17 @@ private
   end
 
   def validate_owning_org_permitted
-    if owning_organisation && !bulk_upload.user.organisation.affiliated_stock_owners.include?(owning_organisation)
-      block_log_creation!
+    return unless owning_organisation
+    return if bulk_upload_organisation.affiliated_stock_owners.include?(owning_organisation)
 
-      if errors[:field_1].blank?
-        errors.add(:field_1, "You do not have permission to add logs for this owning organisation", category: :setup)
-      end
+    block_log_creation!
+
+    return if errors[:field_1].present?
+
+    if bulk_upload.user.support?
+      errors.add(:field_1, "This owning organisation is not affiliated with #{bulk_upload_organisation.name}", category: :setup)
+    else
+      errors.add(:field_1, "You do not have permission to add logs for this owning organisation", category: :setup)
     end
   end
 
@@ -1137,7 +1149,7 @@ private
     attributes["renewal"] = renewal
     attributes["scheme"] = scheme
     attributes["location"] = location
-    attributes["assigned_to"] = assigned_to || bulk_upload.user
+    attributes["assigned_to"] = assigned_to || (bulk_upload.user.support? ? nil : bulk_upload.user)
     attributes["created_by"] = bulk_upload.user
     attributes["needstype"] = field_4
     attributes["rent_type"] = RENT_TYPE_BU_MAPPING[field_11]
@@ -1625,4 +1637,8 @@ private
   def reason_is_other?
     field_98 == 20
   end
+
+  def bulk_upload_organisation
+    Organisation.find(bulk_upload.organisation_id)
+  end
 end
diff --git a/app/services/bulk_upload/sales/year2024/row_parser.rb b/app/services/bulk_upload/sales/year2024/row_parser.rb
index 8be08d62f..0b7a70c27 100644
--- a/app/services/bulk_upload/sales/year2024/row_parser.rb
+++ b/app/services/bulk_upload/sales/year2024/row_parser.rb
@@ -462,6 +462,7 @@ class BulkUpload::Sales::Year2024::RowParser
 
   validate :validate_assigned_to_exists, on: :after_log
   validate :validate_assigned_to_related, on: :after_log
+  validate :validate_assigned_to_when_support, on: :after_log
   validate :validate_managing_org_related, on: :after_log
   validate :validate_relevant_collection_window, on: :after_log
   validate :validate_incomplete_soft_validations, on: :after_log
@@ -925,7 +926,7 @@ private
 
     attributes["owning_organisation"] = owning_organisation
     attributes["managing_organisation"] = managing_organisation
-    attributes["assigned_to"] = assigned_to || bulk_upload.user
+    attributes["assigned_to"] = assigned_to || (bulk_upload.user.support? ? nil : bulk_upload.user)
     attributes["created_by"] = bulk_upload.user
     attributes["hhregres"] = field_72
     attributes["hhregresstill"] = field_73
@@ -1302,12 +1303,17 @@ private
   end
 
   def validate_owning_org_permitted
-    if owning_organisation && !bulk_upload.user.organisation.affiliated_stock_owners.include?(owning_organisation)
-      block_log_creation!
+    return unless owning_organisation
+    return if bulk_upload_organisation.affiliated_stock_owners.include?(owning_organisation)
 
-      if errors[:field_1].blank?
-        errors.add(:field_1, "You do not have permission to add logs for this owning organisation", category: :setup)
-      end
+    block_log_creation!
+
+    return if errors[:field_1].present?
+
+    if bulk_upload.user.support?
+      errors.add(:field_1, "This owning organisation is not affiliated with #{bulk_upload_organisation.name}", category: :setup)
+    else
+      errors.add(:field_1, "You do not have permission to add logs for this owning organisation", category: :setup)
     end
   end
 
@@ -1319,6 +1325,12 @@ private
     end
   end
 
+  def validate_assigned_to_when_support
+    if field_3.blank? && bulk_upload.user.support?
+      errors.add(:field_3, category: :setup, message: I18n.t("validations.not_answered", question: "what is the CORE username of the account this sales log should be assigned to?"))
+    end
+  end
+
   def validate_assigned_to_related
     return unless assigned_to
     return if assigned_to.organisation == owning_organisation || assigned_to.organisation == managing_organisation
@@ -1492,4 +1504,8 @@ private
   def valid_nationality_options
     %w[0] + GlobalConstants::COUNTRIES_ANSWER_OPTIONS.keys # 0 is "Prefers not to say"
   end
+
+  def bulk_upload_organisation
+    Organisation.find(bulk_upload.organisation_id)
+  end
 end
diff --git a/app/views/bulk_upload_lettings_logs/forms/checking_file.html.erb b/app/views/bulk_upload_lettings_logs/forms/checking_file.html.erb
index 7524072a5..2e6d4cd10 100644
--- a/app/views/bulk_upload_lettings_logs/forms/checking_file.html.erb
+++ b/app/views/bulk_upload_lettings_logs/forms/checking_file.html.erb
@@ -6,6 +6,7 @@
   <div class="govuk-grid-column-two-thirds">
     <%= form_with model: @form, scope: :form, url: bulk_upload_lettings_log_path(id: "prepare-your-file"), method: :patch do |f| %>
       <%= f.hidden_field :year %>
+      <%= f.hidden_field :organisation_id %>
 
       <span class="govuk-caption-l">Upload lettings logs in bulk (<%= @form.year_combo %>)</span>
       <h1 class="govuk-heading-l">We’re checking the file</h1>
diff --git a/app/views/bulk_upload_lettings_logs/forms/needstype.erb b/app/views/bulk_upload_lettings_logs/forms/needstype.erb
index 6deec7e1d..644dd9f5f 100644
--- a/app/views/bulk_upload_lettings_logs/forms/needstype.erb
+++ b/app/views/bulk_upload_lettings_logs/forms/needstype.erb
@@ -7,6 +7,7 @@
     <%= form_with model: @form, scope: :form, url: bulk_upload_lettings_log_path(id: "needstype"), method: :patch do |f| %>
       <%= f.govuk_error_summary %>
       <%= f.hidden_field :year %>
+      <%= f.hidden_field :organisation_id %>
 
       <%= f.govuk_collection_radio_buttons :needstype,
             @form.options,
diff --git a/app/views/bulk_upload_lettings_logs/forms/prepare_your_file_2024.html.erb b/app/views/bulk_upload_lettings_logs/forms/prepare_your_file_2024.html.erb
index 45ce4b385..7657396f1 100644
--- a/app/views/bulk_upload_lettings_logs/forms/prepare_your_file_2024.html.erb
+++ b/app/views/bulk_upload_lettings_logs/forms/prepare_your_file_2024.html.erb
@@ -6,6 +6,7 @@
   <div class="govuk-grid-column-two-thirds">
     <%= form_with model: @form, scope: :form, url: bulk_upload_lettings_log_path(id: "prepare-your-file"), method: :patch do |f| %>
       <%= f.hidden_field :year %>
+      <%= f.hidden_field :organisation_id %>
 
       <span class="govuk-caption-l">Upload lettings logs in bulk (<%= @form.year_combo %>)</span>
       <h1 class="govuk-heading-l">Prepare your file</h1>
diff --git a/app/views/bulk_upload_lettings_logs/forms/upload_your_file.html.erb b/app/views/bulk_upload_lettings_logs/forms/upload_your_file.html.erb
index bbafc28b3..2814eb1ea 100644
--- a/app/views/bulk_upload_lettings_logs/forms/upload_your_file.html.erb
+++ b/app/views/bulk_upload_lettings_logs/forms/upload_your_file.html.erb
@@ -7,6 +7,7 @@
     <%= form_with model: @form, scope: :form, url: bulk_upload_lettings_log_path(id: "upload-your-file"), method: :patch do |f| %>
       <%= f.hidden_field :year %>
       <%= f.hidden_field :needstype %>
+      <%= f.hidden_field :organisation_id %>
 
       <%= f.govuk_error_summary %>
 
diff --git a/app/views/bulk_upload_lettings_logs/forms/year.html.erb b/app/views/bulk_upload_lettings_logs/forms/year.html.erb
index 8ba1c280f..4fef16dd7 100644
--- a/app/views/bulk_upload_lettings_logs/forms/year.html.erb
+++ b/app/views/bulk_upload_lettings_logs/forms/year.html.erb
@@ -4,6 +4,7 @@
 
 <%= form_with model: @form, scope: :form, url: bulk_upload_lettings_log_path(id: "year"), method: :patch do |f| %>
   <%= f.govuk_error_summary %>
+  <%= f.hidden_field :organisation_id %>
 
   <%= f.govuk_collection_radio_buttons :year,
         @form.options,
diff --git a/app/views/bulk_upload_lettings_results/show.html.erb b/app/views/bulk_upload_lettings_results/show.html.erb
index 30a6fd585..15c486b91 100644
--- a/app/views/bulk_upload_lettings_results/show.html.erb
+++ b/app/views/bulk_upload_lettings_results/show.html.erb
@@ -25,4 +25,4 @@
   </div>
 </div>
 
-<%= govuk_button_link_to "Upload your file again", start_bulk_upload_lettings_logs_path %>
+<%= govuk_button_link_to "Upload your file again", start_bulk_upload_lettings_logs_path(organisation_id: @bulk_upload.organisation_id) %>
diff --git a/app/views/bulk_upload_lettings_results/summary.html.erb b/app/views/bulk_upload_lettings_results/summary.html.erb
index b144793bf..8a59e8999 100644
--- a/app/views/bulk_upload_lettings_results/summary.html.erb
+++ b/app/views/bulk_upload_lettings_results/summary.html.erb
@@ -29,4 +29,4 @@
   <% end %>
 </div>
 
-<%= govuk_button_link_to "Upload your file again", start_bulk_upload_lettings_logs_path %>
+<%= govuk_button_link_to "Upload your file again", start_bulk_upload_lettings_logs_path(organisation_id: @bulk_upload.organisation_id) %>
diff --git a/app/views/bulk_upload_sales_logs/forms/checking_file.html.erb b/app/views/bulk_upload_sales_logs/forms/checking_file.html.erb
index c47a97d5e..8bcef5cad 100644
--- a/app/views/bulk_upload_sales_logs/forms/checking_file.html.erb
+++ b/app/views/bulk_upload_sales_logs/forms/checking_file.html.erb
@@ -6,6 +6,7 @@
   <div class="govuk-grid-column-two-thirds">
     <%= form_with model: @form, scope: :form, url: bulk_upload_sales_log_path(id: "prepare-your-file"), method: :patch do |f| %>
       <%= f.hidden_field :year %>
+      <%= f.hidden_field :organisation_id %><%= f.hidden_field :organisation_id %>
 
       <span class="govuk-caption-l">Upload sales logs in bulk (<%= @form.year_combo %>)</span>
       <h1 class="govuk-heading-l">We’re checking the file</h1>
diff --git a/app/views/bulk_upload_sales_logs/forms/prepare_your_file_2024.html.erb b/app/views/bulk_upload_sales_logs/forms/prepare_your_file_2024.html.erb
index 81c947e15..2a64de689 100644
--- a/app/views/bulk_upload_sales_logs/forms/prepare_your_file_2024.html.erb
+++ b/app/views/bulk_upload_sales_logs/forms/prepare_your_file_2024.html.erb
@@ -6,6 +6,7 @@
   <div class="govuk-grid-column-two-thirds">
     <%= form_with model: @form, scope: :form, url: bulk_upload_sales_log_path(id: "prepare-your-file"), method: :patch do |f| %>
       <%= f.hidden_field :year %>
+      <%= f.hidden_field :organisation_id %>
 
       <span class="govuk-caption-l">Upload sales logs in bulk (<%= @form.year_combo %>)</span>
       <h1 class="govuk-heading-l">Prepare your file</h1>
diff --git a/app/views/bulk_upload_sales_logs/forms/upload_your_file.html.erb b/app/views/bulk_upload_sales_logs/forms/upload_your_file.html.erb
index 36e7240dc..75350ae9e 100644
--- a/app/views/bulk_upload_sales_logs/forms/upload_your_file.html.erb
+++ b/app/views/bulk_upload_sales_logs/forms/upload_your_file.html.erb
@@ -6,6 +6,7 @@
   <div class="govuk-grid-column-two-thirds">
     <%= form_with model: @form, scope: :form, url: bulk_upload_sales_log_path(id: "upload-your-file"), method: :patch do |f| %>
       <%= f.hidden_field :year %>
+      <%= f.hidden_field :organisation_id %>
 
       <%= f.govuk_error_summary %>
 
diff --git a/app/views/bulk_upload_sales_logs/forms/year.html.erb b/app/views/bulk_upload_sales_logs/forms/year.html.erb
index d8aa09172..2aaa7c0f8 100644
--- a/app/views/bulk_upload_sales_logs/forms/year.html.erb
+++ b/app/views/bulk_upload_sales_logs/forms/year.html.erb
@@ -4,6 +4,7 @@
 
 <%= form_with model: @form, scope: :form, url: bulk_upload_sales_log_path(id: "year"), method: :patch do |f| %>
   <%= f.govuk_error_summary %>
+  <%= f.hidden_field :organisation_id %>
 
   <%= f.govuk_collection_radio_buttons :year,
         @form.options,
diff --git a/app/views/bulk_upload_sales_results/show.html.erb b/app/views/bulk_upload_sales_results/show.html.erb
index 0d645db33..776fdfa2f 100644
--- a/app/views/bulk_upload_sales_results/show.html.erb
+++ b/app/views/bulk_upload_sales_results/show.html.erb
@@ -25,4 +25,4 @@
   </div>
 </div>
 
-<%= govuk_button_link_to "Upload your file again", start_bulk_upload_sales_logs_path %>
+<%= govuk_button_link_to "Upload your file again", start_bulk_upload_sales_logs_path(organisation_id: @bulk_upload.organisation_id) %>
diff --git a/app/views/bulk_upload_sales_results/summary.html.erb b/app/views/bulk_upload_sales_results/summary.html.erb
index 0fa51b9dc..0e423621d 100644
--- a/app/views/bulk_upload_sales_results/summary.html.erb
+++ b/app/views/bulk_upload_sales_results/summary.html.erb
@@ -29,4 +29,4 @@
   <% end %>
 </div>
 
-<%= govuk_button_link_to "Upload your file again", start_bulk_upload_sales_logs_path %>
+<%= govuk_button_link_to "Upload your file again", start_bulk_upload_sales_logs_path(organisation_id: @bulk_upload.organisation_id) %>
diff --git a/app/views/logs/_create_for_org_actions.html.erb b/app/views/logs/_create_for_org_actions.html.erb
index f6ed9ad82..0564e678a 100644
--- a/app/views/logs/_create_for_org_actions.html.erb
+++ b/app/views/logs/_create_for_org_actions.html.erb
@@ -1,10 +1,12 @@
 <div class="govuk-button-group app-filter-toggle">
   <% if @organisation.data_protection_confirmed? %>
     <% if current_page?(controller: 'organisations', action: 'lettings_logs') %>
-      <%= govuk_button_to "Create a new lettings log for this organisation", lettings_logs_path(lettings_log: { owning_organisation_id: @organisation.id }, method: :post) %>
-    <% end %>
+      <%= govuk_button_to "Create a new lettings log for this organisation", lettings_logs_path(lettings_log: { owning_organisation_id: @organisation.id }, method: :post), class: "govuk-!-margin-right-6" %>
+      <%= govuk_button_link_to "Upload lettings logs in bulk", bulk_upload_lettings_log_path(id: "start", organisation_id: @organisation.id), secondary: true %>
+<% end %>
     <% if current_page?(controller: 'organisations', action: 'sales_logs') %>
-      <%= govuk_button_to "Create a new sales log for this organisation", sales_logs_path(sales_log: { owning_organisation_id: @organisation.id }, method: :post) %>
-    <% end %>
+      <%= govuk_button_to "Create a new sales log for this organisation", sales_logs_path(sales_log: { owning_organisation_id: @organisation.id }, method: :post), class: "govuk-!-margin-right-6" %>
+      <%= govuk_button_link_to "Upload sales logs in bulk", bulk_upload_sales_log_path(id: "start", organisation_id: @organisation.id), secondary: true %>
+<% end %>
   <% end %>
 </div>
diff --git a/db/migrate/20240905092332_add_organisation_id_to_bulk_uploads.rb b/db/migrate/20240905092332_add_organisation_id_to_bulk_uploads.rb
new file mode 100644
index 000000000..d9f4f16da
--- /dev/null
+++ b/db/migrate/20240905092332_add_organisation_id_to_bulk_uploads.rb
@@ -0,0 +1,5 @@
+class AddOrganisationIdToBulkUploads < ActiveRecord::Migration[7.0]
+  def change
+    add_column :bulk_uploads, :organisation_id, :integer
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index cd7708957..4d6f18b84 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -42,6 +42,7 @@ ActiveRecord::Schema[7.0].define(version: 2024_09_23_145326) do
     t.text "choice"
     t.integer "total_logs_count"
     t.string "rent_type_fix_status", default: "not_applied"
+    t.integer "organisation_id"
     t.integer "moved_user_id"
     t.index ["identifier"], name: "index_bulk_uploads_on_identifier", unique: true
     t.index ["user_id"], name: "index_bulk_uploads_on_user_id"
diff --git a/spec/factories/bulk_upload.rb b/spec/factories/bulk_upload.rb
index c848fb071..cefe95c2b 100644
--- a/spec/factories/bulk_upload.rb
+++ b/spec/factories/bulk_upload.rb
@@ -9,6 +9,7 @@ FactoryBot.define do
     sequence(:filename) { |n| "bulk-upload-#{n}.csv" }
     needstype { 1 }
     rent_type_fix_status { BulkUpload.rent_type_fix_statuses.values.sample }
+    organisation_id { user.organisation_id }
 
     trait(:sales) do
       log_type { BulkUpload.log_types[:sales] }
diff --git a/spec/features/organisation_spec.rb b/spec/features/organisation_spec.rb
index 1867285eb..3d65cda87 100644
--- a/spec/features/organisation_spec.rb
+++ b/spec/features/organisation_spec.rb
@@ -139,6 +139,10 @@ RSpec.describe "User Features" do
         expect(page).to have_button("Create a new lettings log for this organisation")
       end
 
+      it "shows a upload lettings logs in bulk link" do
+        expect(page).to have_link("Upload lettings logs in bulk")
+      end
+
       context "when creating a log for that organisation" do
         it "pre-fills the value for owning organisation for that log" do
           click_button("Create a new lettings log for this organisation")
@@ -230,6 +234,10 @@ RSpec.describe "User Features" do
         expect(page).to have_button("Create a new sales log for this organisation")
       end
 
+      it "shows a upload sales logs in bulk link" do
+        expect(page).to have_link("Upload sales logs in bulk")
+      end
+
       context "when creating a log for that organisation" do
         it "pre-fills the value for owning organisation for that log" do
           click_button("Create a new sales log for this organisation")
diff --git a/spec/services/bulk_upload/lettings/year2024/row_parser_spec.rb b/spec/services/bulk_upload/lettings/year2024/row_parser_spec.rb
index 3faa0a699..68de5d22b 100644
--- a/spec/services/bulk_upload/lettings/year2024/row_parser_spec.rb
+++ b/spec/services/bulk_upload/lettings/year2024/row_parser_spec.rb
@@ -815,6 +815,23 @@ RSpec.describe BulkUpload::Lettings::Year2024::RowParser do
         end
       end
 
+      context "when blank and bulk upload user is support" do
+        let(:bulk_upload) { create(:bulk_upload, :sales, user: create(:user, :support), year: 2024) }
+
+        let(:attributes) { setup_section_params.merge(bulk_upload:, field_3: nil) }
+
+        it "is not permitted" do
+          parser.valid?
+          expect(parser.errors[:field_3]).to be_present
+          expect(parser.errors[:field_3]).to include("You must answer what is the CORE username of the account this letting log should be assigned to?")
+        end
+
+        it "blocks log creation" do
+          parser.valid?
+          expect(parser).to be_block_log_creation
+        end
+      end
+
       context "when user could not be found" do
         let(:attributes) { { bulk_upload:, field_3: "idonotexist@example.com" } }
 
@@ -1439,6 +1456,43 @@ RSpec.describe BulkUpload::Lettings::Year2024::RowParser do
           expect(parser.errors[:field_10]).to include(/Enter a date when the owning and managing organisation was active/)
         end
       end
+
+      context "when user is an unaffiliated non-support user and bulk upload organisation is affiliated with the owning organisation" do
+        let(:affiliated_org) { create(:organisation, :with_old_visible_id) }
+        let(:unaffiliated_user) { create(:user, organisation: create(:organisation)) }
+        let(:attributes) { { bulk_upload:, field_1: affiliated_org.old_visible_id } }
+        let(:organisation_id) { unaffiliated_user.organisation_id }
+
+        before do
+          create(:organisation_relationship, parent_organisation: owning_org, child_organisation: affiliated_org)
+          bulk_upload.update!(organisation_id:, user: unaffiliated_user)
+        end
+
+        it "blocks log creation and adds an error to field_1" do
+          parser = described_class.new(attributes)
+          parser.valid?
+          expect(parser).to be_block_log_creation
+          expect(parser.errors[:field_1]).to include("You do not have permission to add logs for this owning organisation")
+        end
+      end
+
+      context "when user is an unaffiliated support user and bulk upload organisation is affiliated with the owning organisation" do
+        let(:affiliated_org) { create(:organisation, :with_old_visible_id) }
+        let(:unaffiliated_support_user) { create(:user, :support, organisation: create(:organisation)) }
+        let(:attributes) { { bulk_upload:, field_1: affiliated_org.old_visible_id } }
+        let(:organisation_id) { affiliated_org.id }
+
+        before do
+          create(:organisation_relationship, parent_organisation: owning_org, child_organisation: affiliated_org)
+          bulk_upload.update!(organisation_id:, user: unaffiliated_support_user)
+        end
+
+        it "does not block log creation and does not add an error to field_1" do
+          parser = described_class.new(attributes)
+          parser.valid?
+          expect(parser.errors[:field_1]).not_to include("You do not have permission to add logs for this owning organisation")
+        end
+      end
     end
 
     describe "#field_2" do # managing org
diff --git a/spec/services/bulk_upload/sales/year2024/row_parser_spec.rb b/spec/services/bulk_upload/sales/year2024/row_parser_spec.rb
index e428f7792..ca8f29e92 100644
--- a/spec/services/bulk_upload/sales/year2024/row_parser_spec.rb
+++ b/spec/services/bulk_upload/sales/year2024/row_parser_spec.rb
@@ -554,6 +554,43 @@ RSpec.describe BulkUpload::Sales::Year2024::RowParser do
           expect(parser.errors[:field_6]).to include(/Enter a date when the owning organisation was active/)
         end
       end
+
+      context "when user is an unaffiliated non-support user and bulk upload organisation is affiliated with the owning organisation" do
+        let(:affiliated_org) { create(:organisation, :with_old_visible_id) }
+        let(:unaffiliated_user) { create(:user, organisation: create(:organisation)) }
+        let(:attributes) { { bulk_upload:, field_1: affiliated_org.old_visible_id } }
+        let(:organisation_id) { unaffiliated_user.organisation_id }
+
+        before do
+          create(:organisation_relationship, parent_organisation: owning_org, child_organisation: affiliated_org)
+          bulk_upload.update!(organisation_id:, user: unaffiliated_user)
+        end
+
+        it "blocks log creation and adds an error to field_1" do
+          parser = described_class.new(attributes)
+          parser.valid?
+          expect(parser).to be_block_log_creation
+          expect(parser.errors[:field_1]).to include("You do not have permission to add logs for this owning organisation")
+        end
+      end
+
+      context "when user is an unaffiliated support user and bulk upload organisation is affiliated with the owning organisation" do
+        let(:affiliated_org) { create(:organisation, :with_old_visible_id) }
+        let(:unaffiliated_support_user) { create(:user, :support, organisation: create(:organisation)) }
+        let(:attributes) { { bulk_upload:, field_1: affiliated_org.old_visible_id } }
+        let(:organisation_id) { affiliated_org.id }
+
+        before do
+          create(:organisation_relationship, parent_organisation: owning_org, child_organisation: affiliated_org)
+          bulk_upload.update!(organisation_id:, user: unaffiliated_support_user)
+        end
+
+        it "does not block log creation and does not add an error to field_1" do
+          parser = described_class.new(attributes)
+          parser.valid?
+          expect(parser.errors[:field_1]).not_to include("You do not have permission to add logs for this owning organisation")
+        end
+      end
     end
 
     describe "#field_3" do # username for assigned_to
@@ -576,6 +613,23 @@ RSpec.describe BulkUpload::Sales::Year2024::RowParser do
         end
       end
 
+      context "when blank and bulk upload user is support" do
+        let(:bulk_upload) { create(:bulk_upload, :sales, user: create(:user, :support), year: 2024) }
+
+        let(:attributes) { setup_section_params.merge(bulk_upload:, field_3: nil) }
+
+        it "is not permitted" do
+          parser.valid?
+          expect(parser.errors[:field_3]).to be_present
+          expect(parser.errors[:field_3]).to include("You must answer what is the CORE username of the account this sales log should be assigned to?")
+        end
+
+        it "blocks log creation" do
+          parser.valid?
+          expect(parser).to be_block_log_creation
+        end
+      end
+
       context "when user could not be found" do
         let(:attributes) { { bulk_upload:, field_3: "idonotexist@example.com" } }