diff --git a/app/models/form/lettings/questions/nationality_all_group.rb b/app/models/form/lettings/questions/nationality_all_group.rb
index 065a4e245..2ba9e5cde 100644
--- a/app/models/form/lettings/questions/nationality_all_group.rb
+++ b/app/models/form/lettings/questions/nationality_all_group.rb
@@ -16,6 +16,6 @@ class Form::Lettings::Questions::NationalityAllGroup < ::Form::Question
   ANSWER_OPTIONS = {
     "826" => { "value" => "United Kingdom" },
     "12" => { "value" => "Other" },
-    "13" => { "value" => "Tenant prefers not to say" },
+    "0" => { "value" => "Tenant prefers not to say" },
   }.freeze
 end
diff --git a/app/models/form/sales/questions/nationality_all_group.rb b/app/models/form/sales/questions/nationality_all_group.rb
index 349485188..c9b1e71bc 100644
--- a/app/models/form/sales/questions/nationality_all_group.rb
+++ b/app/models/form/sales/questions/nationality_all_group.rb
@@ -15,6 +15,6 @@ class Form::Sales::Questions::NationalityAllGroup < ::Form::Question
   ANSWER_OPTIONS = {
     "826" => { "value" => "United Kingdom" },
     "12" => { "value" => "Other" },
-    "13" => { "value" => "Buyer prefers not to say" },
+    "0" => { "value" => "Buyer prefers not to say" },
   }.freeze
 end
diff --git a/app/models/log.rb b/app/models/log.rb
index 5de8b924c..10e2078ee 100644
--- a/app/models/log.rb
+++ b/app/models/log.rb
@@ -210,7 +210,7 @@ class Log < ApplicationRecord
   end
 
   def nationality_uk_or_prefers_not_to_say?
-    nationality_all_group == 13 || nationality_all_group == 826
+    nationality_all_group == 0 || nationality_all_group == 826
   end
 
 private
diff --git a/app/models/sales_log.rb b/app/models/sales_log.rb
index 1591e4a14..4e8d64f18 100644
--- a/app/models/sales_log.rb
+++ b/app/models/sales_log.rb
@@ -475,6 +475,6 @@ class SalesLog < Log
   end
 
   def nationality2_uk_or_prefers_not_to_say?
-    nationality_all_buyer2_group == 13 || nationality_all_buyer2_group == 826
+    nationality_all_buyer2_group == 0 || nationality_all_buyer2_group == 826
   end
 end
diff --git a/spec/models/lettings_log_spec.rb b/spec/models/lettings_log_spec.rb
index 7d2fcc8c2..5c55d87cb 100644
--- a/spec/models/lettings_log_spec.rb
+++ b/spec/models/lettings_log_spec.rb
@@ -2359,7 +2359,7 @@ RSpec.describe LettingsLog do
       end
 
       it "correctly derives nationality_all when it's prefers not to say" do
-        expect { lettings_log.update!(nationality_all_group: 13, declaration: 1) }.to change(lettings_log, :nationality_all).to 13
+        expect { lettings_log.update!(nationality_all_group: 0, declaration: 1) }.to change(lettings_log, :nationality_all).to 0
       end
 
       it "does not derive nationality_all when it's other or not given" do
diff --git a/spec/models/sales_log_spec.rb b/spec/models/sales_log_spec.rb
index 87c9b32f4..42aa64fec 100644
--- a/spec/models/sales_log_spec.rb
+++ b/spec/models/sales_log_spec.rb
@@ -585,8 +585,8 @@ RSpec.describe SalesLog, type: :model do
       end
 
       it "correctly derives nationality_all/nationality_all_buyer2 when buyer prefers not to say" do
-        expect { sales_log.update!(nationality_all_group: 13) }.to change(sales_log, :nationality_all).to 13
-        expect { sales_log.update!(nationality_all_buyer2_group: 13) }.to change(sales_log, :nationality_all_buyer2).to 13
+        expect { sales_log.update!(nationality_all_group: 0) }.to change(sales_log, :nationality_all).to 0
+        expect { sales_log.update!(nationality_all_buyer2_group: 0) }.to change(sales_log, :nationality_all_buyer2).to 0
       end
 
       it "does not derive nationality_all/nationality_all_buyer2 when it is other or not given" do