diff --git a/app/services/bulk_upload/lettings/validator.rb b/app/services/bulk_upload/lettings/validator.rb
index 1a0e6ecf5..ec18e946b 100644
--- a/app/services/bulk_upload/lettings/validator.rb
+++ b/app/services/bulk_upload/lettings/validator.rb
@@ -43,8 +43,10 @@ class BulkUpload::Lettings::Validator
   def create_logs?
     return false if any_setup_errors?
     return false if row_parsers.any?(&:block_log_creation?)
+    return false if any_logs_already_exist?
+    return false if any_logs_invalid?
 
-    row_parsers.all? { |row_parser| row_parser.log.valid? }
+    true
   end
 
   def self.question_for_field(field)
@@ -59,8 +61,6 @@ class BulkUpload::Lettings::Validator
       .positive?
   end
 
-private
-
   def over_column_error_threshold?
     fields = ("field_1".."field_134").to_a
     percentage_threshold = (row_parsers.size * COLUMN_PERCENTAGE_ERROR_THRESHOLD).ceil
@@ -74,6 +74,16 @@ private
     end
   end
 
+  def any_logs_already_exist?
+    row_parsers.any?(&:log_already_exists?)
+  end
+
+private
+
+  def any_logs_invalid?
+    row_parsers.any? { |row_parser| row_parser.log.invalid? }
+  end
+
   def csv_parser
     @csv_parser ||= case bulk_upload.year
                     when 2022
diff --git a/app/services/bulk_upload/lettings/year2022/row_parser.rb b/app/services/bulk_upload/lettings/year2022/row_parser.rb
index 650c3e896..5c811da7f 100644
--- a/app/services/bulk_upload/lettings/year2022/row_parser.rb
+++ b/app/services/bulk_upload/lettings/year2022/row_parser.rb
@@ -307,6 +307,7 @@ class BulkUpload::Lettings::Year2022::RowParser
   validate :validate_no_disabled_needs_conjunction, on: :after_log
   validate :validate_dont_know_disabled_needs_conjunction, on: :after_log
   validate :validate_no_and_dont_know_disabled_needs_conjunction, on: :after_log
+  validate :validate_if_log_already_exists, on: :after_log
 
   validate :validate_owning_org_data_given, on: :after_log
   validate :validate_owning_org_exists, on: :after_log
@@ -392,6 +393,10 @@ class BulkUpload::Lettings::Year2022::RowParser
     field_100
   end
 
+  def log_already_exists?
+    LettingsLog.exists?(duplicity_check_fields.index_with { |field| log.public_send(field) })
+  end
+
 private
 
   def validate_declaration_acceptance
@@ -436,6 +441,18 @@ private
     @created_by ||= User.find_by(email: field_112)
   end
 
+  def duplicity_check_fields
+    %w[
+      startdate
+      age1
+      sex1
+      ecstat1
+      owning_organisation
+      tcharge
+      propcode
+    ]
+  end
+
   def validate_location_related
     return if scheme.blank? || location.blank?
 
@@ -694,6 +711,25 @@ private
     log.form.setup_sections[0].subsections[0].questions.include?(question)
   end
 
+  def validate_if_log_already_exists
+    if log_already_exists?
+      error_message = "This is a duplicate log"
+
+      errors.add(:field_12, error_message) # age1
+      errors.add(:field_20, error_message) # sex1
+      errors.add(:field_35, error_message) # ecstat1
+
+      errors.add(:field_84, error_message) # tcharge
+
+      errors.add(:field_96, error_message) # startdate
+      errors.add(:field_97, error_message) # startdate
+      errors.add(:field_98, error_message) # startdate
+
+      errors.add(:field_100, error_message) # propcode
+      errors.add(:field_111, error_message) # owning_organisation
+    end
+  end
+
   def field_mapping_for_errors
     {
       lettype: [:field_1],
@@ -893,18 +929,10 @@ private
     Organisation.find_by_id_on_multiple_fields(field_111)
   end
 
-  def owning_organisation_id
-    owning_organisation&.id
-  end
-
   def managing_organisation
     Organisation.find_by_id_on_multiple_fields(field_113)
   end
 
-  def managing_organisation_id
-    managing_organisation&.id
-  end
-
   def attributes_for_log
     attributes = {}
 
@@ -913,8 +941,8 @@ private
     attributes["la"] = field_107
     attributes["postcode_known"] = postcode_known
     attributes["postcode_full"] = postcode_full
-    attributes["owning_organisation_id"] = owning_organisation_id
-    attributes["managing_organisation_id"] = managing_organisation_id
+    attributes["owning_organisation"] = owning_organisation
+    attributes["managing_organisation"] = managing_organisation
     attributes["renewal"] = renewal
     attributes["scheme"] = scheme
     attributes["location"] = location
diff --git a/app/services/bulk_upload/processor.rb b/app/services/bulk_upload/processor.rb
index 49d44261f..adc0de0e3 100644
--- a/app/services/bulk_upload/processor.rb
+++ b/app/services/bulk_upload/processor.rb
@@ -54,9 +54,14 @@ private
   end
 
   def send_correct_and_upload_again_mail
-    BulkUploadMailer
-      .send_correct_and_upload_again_mail(bulk_upload:)
-      .deliver_later
+    BulkUploadMailer.send_correct_and_upload_again_mail(
+      bulk_upload:,
+      errors: {
+        any_setup_sections_incomplete: validator.any_setup_sections_incomplete?,
+        over_column_error_threshold: validator.over_column_error_threshold?,
+        any_logs_already_exist: validator.any_logs_already_exist?,
+      },
+    ).deliver_later
   end
 
   def send_success_mail
diff --git a/spec/mailers/bulk_upload_mailer_spec.rb b/spec/mailers/bulk_upload_mailer_spec.rb
index 20f78de4d..e28a5dd70 100644
--- a/spec/mailers/bulk_upload_mailer_spec.rb
+++ b/spec/mailers/bulk_upload_mailer_spec.rb
@@ -90,10 +90,11 @@ RSpec.describe BulkUploadMailer do
             year_combo: bulk_upload.year_combo,
             lettings_or_sales: bulk_upload.log_type,
             summary_report_link: "http://localhost:3000/lettings-logs/bulk-upload-results/#{bulk_upload.id}",
+            error_description: "Please correct your data export and upload again.\n",
           },
         )
 
-        mailer.send_correct_and_upload_again_mail(bulk_upload:)
+        mailer.send_correct_and_upload_again_mail(bulk_upload:, errors: {})
       end
     end
   end
diff --git a/spec/services/bulk_upload/lettings/year2022/row_parser_spec.rb b/spec/services/bulk_upload/lettings/year2022/row_parser_spec.rb
index f092b141e..3fe08135f 100644
--- a/spec/services/bulk_upload/lettings/year2022/row_parser_spec.rb
+++ b/spec/services/bulk_upload/lettings/year2022/row_parser_spec.rb
@@ -216,6 +216,35 @@ RSpec.describe BulkUpload::Lettings::Year2022::RowParser do
           expect(questions.map(&:id).size).to eq(0)
           expect(questions.map(&:id)).to eql([])
         end
+
+        context "when the log already exists in the db" do
+          before do
+            parser.log.save!
+          end
+
+          it "is not a valid row" do
+            expect(parser).not_to be_valid
+          end
+
+          it "adds an error to all (and only) the fields used to determine duplicity" do
+            parser.valid?
+
+            error_message = "This is a duplicate log"
+
+            expected_errors = {
+              field_12: [error_message], # age1
+              field_20: [error_message], # sex1
+              field_35: [error_message], # ecstat1
+              field_84: [error_message], # tcharge
+              field_96: [error_message], # startdate
+              field_97: [error_message], # startdate
+              field_98: [error_message], # startdate
+              field_100: [error_message], # propcode
+              field_111: [error_message], # owning_organisation
+            }
+            expect(parser.errors.as_json).to eq(expected_errors)
+          end
+        end
       end
     end