Update UPRN known question number

app/models/form/lettings/questions/uprn_known.rb

@@ -22,6 +22,7 @@ class Form::Lettings::Questions::UprnKnown < ::Form::Question
         { "uprn_known" => 1 },
       ],
     }
+    @question_number = QUESTION_NUMBER_FROM_YEAR[form.start_date.year] || QUESTION_NUMBER_FROM_YEAR[QUESTION_NUMBER_FROM_YEAR.keys.max]
   end
 
   ANSWER_OPTIONS = {
@@ -32,4 +33,6 @@ class Form::Lettings::Questions::UprnKnown < ::Form::Question
   def unanswered_error_message
     I18n.t("validations.property.uprn_known.invalid")
   end
+
+  QUESTION_NUMBER_FROM_YEAR = { 2023 => 11, 2024 => 12 }.freeze
 end

spec/models/form/lettings/questions/uprn_known_spec.rb

@@ -5,7 +5,7 @@ RSpec.describe Form::Lettings::Questions::UprnKnown, type: :model do
 
   let(:question_id) { nil }
   let(:question_definition) { nil }
-  let(:page) { instance_double(Form::Page) }
+  let(:page) { instance_double(Form::Page, subsection: instance_double(Form::Subsection, form: instance_double(Form, start_date: Time.zone.local(2023, 4, 1)))) }
 
   it "has correct page" do
     expect(question.page).to eq(page)
@@ -71,4 +71,16 @@ RSpec.describe Form::Lettings::Questions::UprnKnown, type: :model do
       },
     ])
   end
+
+  it "has the correct question_number" do
+    expect(question.question_number).to eq(11)
+  end
+
+  context "with 2024 form" do
+    let(:page) { instance_double(Form::Page, subsection: instance_double(Form::Subsection, form: instance_double(Form, start_date: Time.zone.local(2024, 4, 1)))) }
+
+    it "has the correct question_number" do
+      expect(question.question_number).to eq(12)
+    end
+  end
 end