diff --git a/app/models/derived_variables/sales_log_variables.rb b/app/models/derived_variables/sales_log_variables.rb
index 3f4d61114..f5106f4c0 100644
--- a/app/models/derived_variables/sales_log_variables.rb
+++ b/app/models/derived_variables/sales_log_variables.rb
@@ -20,15 +20,8 @@ module DerivedVariables::SalesLogVariables
 
     if outright_sale? && mortgage_not_used?
       self.deposit = value
-    elsif outright_sale? && mortgage_use_unknown?
-      self.deposit = nil
-    elsif outright_sale? && mortgageused_changed? && !deposit_changed?
-      # Clear when switching to mortgage used
-      self.deposit = nil
-    elsif ownershipsch_changed?(from: 3) &&
-        ((mortgage_not_used? && !mortgageused_changed?) || mortgageused_changed?(from: 2)) &&
-        !deposit_changed?
-      # Clear when switching to to different ownership type
+    elsif outright_sale? && mortgageused_changed?(from: 2, to: 1)
+      # Clear when switching mortgage used from no to yes
       self.deposit = nil
     end
 
diff --git a/app/models/form.rb b/app/models/form.rb
index baae2d9bb..1d58e2f9f 100644
--- a/app/models/form.rb
+++ b/app/models/form.rb
@@ -270,7 +270,7 @@ class Form
                         else
                           questions.reject { |q| %w[radio checkbox].include?(q.type) || q.disable_clearing_if_not_routed_or_dynamic_answer_options }
                         end
-    routed, not_routed = questions_by_type.partition { |q| q.page.routed_to?(log, current_user) || q.derived? }
+    routed, not_routed = questions_by_type.partition { |q| q.page.routed_to?(log, current_user) || q.derived?(log) }
     { routed:, not_routed: }
   end
 
diff --git a/app/models/form/lettings/questions/created_by_id.rb b/app/models/form/lettings/questions/created_by_id.rb
index b2516808e..02176fb4d 100644
--- a/app/models/form/lettings/questions/created_by_id.rb
+++ b/app/models/form/lettings/questions/created_by_id.rb
@@ -6,6 +6,7 @@ class Form::Lettings::Questions::CreatedById < ::Form::Question
     @id = "created_by_id"
     @check_answer_label = "Log owner"
     @header = "Which user are you creating this log for?"
+    @derived = true
     @type = "select"
   end
 
@@ -44,10 +45,6 @@ class Form::Lettings::Questions::CreatedById < ::Form::Question
     present_user(User.find(value))
   end
 
-  def derived?
-    true
-  end
-
 private
 
   def present_user(user)
diff --git a/app/models/form/lettings/questions/managing_organisation.rb b/app/models/form/lettings/questions/managing_organisation.rb
index c9ab1247a..51eccdaac 100644
--- a/app/models/form/lettings/questions/managing_organisation.rb
+++ b/app/models/form/lettings/questions/managing_organisation.rb
@@ -4,6 +4,7 @@ class Form::Lettings::Questions::ManagingOrganisation < ::Form::Question
     @id = "managing_organisation_id"
     @check_answer_label = "Managing agent"
     @header = "Which organisation manages this letting?"
+    @derived = true
     @type = "select"
     @question_number = QUESTION_NUMBER_FROM_YEAR[form.start_date.year] || QUESTION_NUMBER_FROM_YEAR[QUESTION_NUMBER_FROM_YEAR.keys.max] if form.start_date.present?
   end
@@ -62,10 +63,6 @@ class Form::Lettings::Questions::ManagingOrganisation < ::Form::Question
     answer_options[value]
   end
 
-  def derived?
-    true
-  end
-
   def hidden_in_check_answers?(log, user = nil)
     user.nil? || !@page.routed_to?(log, user)
   end
diff --git a/app/models/form/lettings/questions/stock_owner.rb b/app/models/form/lettings/questions/stock_owner.rb
index 758427fc9..682c64247 100644
--- a/app/models/form/lettings/questions/stock_owner.rb
+++ b/app/models/form/lettings/questions/stock_owner.rb
@@ -4,6 +4,7 @@ class Form::Lettings::Questions::StockOwner < ::Form::Question
     @id = "owning_organisation_id"
     @check_answer_label = "Stock owner"
     @header = "Which organisation owns this property?"
+    @derived = true
     @type = "select"
     @question_number = QUESTION_NUMBER_FROM_YEAR[form.start_date.year] || QUESTION_NUMBER_FROM_YEAR[QUESTION_NUMBER_FROM_YEAR.keys.max] if form.start_date.present?
   end
@@ -60,10 +61,6 @@ class Form::Lettings::Questions::StockOwner < ::Form::Question
     answer_options(log, user)[value]
   end
 
-  def derived?
-    true
-  end
-
   def hidden_in_check_answers?(_log, user = nil)
     return false if user.support?
 
diff --git a/app/models/form/question.rb b/app/models/form/question.rb
index 0a486b5bd..0c1611e60 100644
--- a/app/models/form/question.rb
+++ b/app/models/form/question.rb
@@ -99,7 +99,7 @@ class Form::Question
     page.routed_to?(log, nil) && enabled?(log)
   end
 
-  def derived?
+  def derived?(_log)
     !!derived
   end
 
diff --git a/app/models/form/sales/questions/buyer_previous.rb b/app/models/form/sales/questions/buyer_previous.rb
index fe16969d7..b35a67c5e 100644
--- a/app/models/form/sales/questions/buyer_previous.rb
+++ b/app/models/form/sales/questions/buyer_previous.rb
@@ -22,7 +22,7 @@ class Form::Sales::Questions::BuyerPrevious < ::Form::Question
     }
   end
 
-  def derived?
+  def derived?(_log)
     form.start_year_after_2024?
   end
 
diff --git a/app/models/form/sales/questions/created_by_id.rb b/app/models/form/sales/questions/created_by_id.rb
index 4e0e73e27..725361ee4 100644
--- a/app/models/form/sales/questions/created_by_id.rb
+++ b/app/models/form/sales/questions/created_by_id.rb
@@ -6,6 +6,7 @@ class Form::Sales::Questions::CreatedById < ::Form::Question
     @id = "created_by_id"
     @check_answer_label = "Log owner"
     @header = "Which user are you creating this log for?"
+    @derived = true
     @type = "select"
   end
 
@@ -47,10 +48,6 @@ class Form::Sales::Questions::CreatedById < ::Form::Question
     true
   end
 
-  def derived?
-    true
-  end
-
 private
 
   def present_user(user)
diff --git a/app/models/form/sales/questions/deposit_amount.rb b/app/models/form/sales/questions/deposit_amount.rb
index 9c18e3688..72faa818c 100644
--- a/app/models/form/sales/questions/deposit_amount.rb
+++ b/app/models/form/sales/questions/deposit_amount.rb
@@ -10,12 +10,15 @@ class Form::Sales::Questions::DepositAmount < ::Form::Question
     @step = 1
     @width = 5
     @prefix = "£"
-    @derived = true
     @ownershipsch = ownershipsch
     @question_number = QUESTION_NUMBER_FROM_YEAR_AND_OWNERSHIP.fetch(form.start_date.year, QUESTION_NUMBER_FROM_YEAR_AND_OWNERSHIP.max_by { |k, _v| k }.last)[ownershipsch]
     @optional = optional
   end
 
+  def derived?(log)
+    log.outright_sale? && log.mortgage_not_used?
+  end
+
   def selected_answer_option_is_derived?(_log)
     true
   end
diff --git a/app/models/form/sales/questions/managing_organisation.rb b/app/models/form/sales/questions/managing_organisation.rb
index a0e8f2c28..f98dd0100 100644
--- a/app/models/form/sales/questions/managing_organisation.rb
+++ b/app/models/form/sales/questions/managing_organisation.rb
@@ -4,6 +4,7 @@ class Form::Sales::Questions::ManagingOrganisation < ::Form::Question
     @id = "managing_organisation_id"
     @check_answer_label = "Reported by"
     @header = "Which organisation is reporting this sale?"
+    @derived = true
     @type = "select"
     @question_number = QUESTION_NUMBER_FROM_YEAR[form.start_date.year] || QUESTION_NUMBER_FROM_YEAR[QUESTION_NUMBER_FROM_YEAR.keys.max]
   end
@@ -54,10 +55,6 @@ class Form::Sales::Questions::ManagingOrganisation < ::Form::Question
     answer_options[value]
   end
 
-  def derived?
-    true
-  end
-
   def hidden_in_check_answers?(log, user = nil)
     user.nil? || !@page.routed_to?(log, user)
   end
diff --git a/app/models/form/sales/questions/owning_organisation_id.rb b/app/models/form/sales/questions/owning_organisation_id.rb
index 838b770f6..062fbcaaf 100644
--- a/app/models/form/sales/questions/owning_organisation_id.rb
+++ b/app/models/form/sales/questions/owning_organisation_id.rb
@@ -4,6 +4,7 @@ class Form::Sales::Questions::OwningOrganisationId < ::Form::Question
     @id = "owning_organisation_id"
     @check_answer_label = "Owning organisation"
     @header = "Which organisation owns this log?"
+    @derived = true
     @type = "select"
     @question_number = QUESTION_NUMBER_FROM_YEAR[form.start_date.year] || QUESTION_NUMBER_FROM_YEAR[QUESTION_NUMBER_FROM_YEAR.keys.max]
   end
@@ -71,10 +72,6 @@ class Form::Sales::Questions::OwningOrganisationId < ::Form::Question
     answer_options(log, user)[value]
   end
 
-  def derived?
-    true
-  end
-
   def hidden_in_check_answers?(_log, user = nil)
     return false if user.support?
 
diff --git a/app/models/form/subsection.rb b/app/models/form/subsection.rb
index bff8b8e73..25a473e98 100644
--- a/app/models/form/subsection.rb
+++ b/app/models/form/subsection.rb
@@ -29,7 +29,7 @@ class Form::Subsection
 
     qs = applicable_questions(log)
     qs_optional_removed = qs.reject { |q| log.optional_fields.include?(q.id) }
-    return :not_started if qs.count.positive? && qs.all? { |question| question.unanswered?(log) || question.read_only? || question.derived? }
+    return :not_started if qs.count.positive? && qs.all? { |question| question.unanswered?(log) || question.read_only? || question.derived?(log) }
     return :completed if qs_optional_removed.all? { |question| question.completed?(log) }
 
     :in_progress
@@ -49,7 +49,7 @@ class Form::Subsection
 
   def applicable_questions(log)
     questions.select do |q|
-      (q.displayed_to_user?(log) && !q.derived?) || q.is_derived_or_has_inferred_check_answers_value?(log)
+      (q.displayed_to_user?(log) && !q.derived?(log)) || q.is_derived_or_has_inferred_check_answers_value?(log)
     end
   end