diff --git a/app/models/form/sales/questions/buyer1_income.rb b/app/models/form/sales/questions/buyer1_income.rb
index 2b80aec5a..aa4a9df09 100644
--- a/app/models/form/sales/questions/buyer1_income.rb
+++ b/app/models/form/sales/questions/buyer1_income.rb
@@ -7,6 +7,7 @@ class Form::Sales::Questions::Buyer1Income < ::Form::Question
     @type = "numeric"
     @page = page
     @min = 0
+    @max = 999_999
     @step = 1
     @width = 5
     @prefix = "£"
diff --git a/app/models/sales_log.rb b/app/models/sales_log.rb
index 5a2e045bc..2285aa53d 100644
--- a/app/models/sales_log.rb
+++ b/app/models/sales_log.rb
@@ -1,5 +1,6 @@
 class SalesLogValidator < ActiveModel::Validator
   include Validations::Sales::HouseholdValidations
+  include Validations::SharedValidations
 
   def validate(record)
     validation_methods = public_methods.select { |method| method.starts_with?("validate_") }
diff --git a/spec/models/form/sales/questions/buyer1_income_spec.rb b/spec/models/form/sales/questions/buyer1_income_spec.rb
index c37caad43..978e2d0bb 100644
--- a/spec/models/form/sales/questions/buyer1_income_spec.rb
+++ b/spec/models/form/sales/questions/buyer1_income_spec.rb
@@ -54,4 +54,8 @@ RSpec.describe Form::Sales::Questions::Buyer1Income, type: :model do
   it "has the correct check_answers_card_number" do
     expect(question.check_answers_card_number).to eq(1)
   end
+
+  it "has correct max" do
+    expect(question.max).to eq(999_999)
+  end
 end