feat: add initial question number behaviour

app/helpers/question_view_helper.rb

@@ -7,7 +7,7 @@ module QuestionViewHelper
 
   def legend(question, page_header, conditional)
     {
-      text: question.header.html_safe,
+      text: [question.question_number_string, question.header.html_safe].compact.join(" - "),
       size: label_size(page_header, conditional),
       tag: label_tag(page_header, conditional),
     }

app/models/form/question.rb

@@ -4,7 +4,7 @@ class Form::Question
                 :conditional_for, :readonly, :answer_options, :page, :check_answer_label,
                 :inferred_answers, :hidden_in_check_answers, :inferred_check_answers_value,
                 :guidance_partial, :prefix, :suffix, :requires_js, :fields_added, :derived,
-                :check_answers_card_number, :unresolved_hint_text
+                :check_answers_card_number, :unresolved_hint_text, :question_number
 
   module GuidancePosition
     TOP = 1
@@ -40,6 +40,7 @@ class Form::Question
       @fields_added = hsh["fields_added"]
       @check_answers_card_number = hsh["check_answers_card_number"] || 0
       @unresolved_hint_text = hsh["unresolved_hint_text"]
+      @question_number = hsh["question_number"]
     end
   end
 
@@ -258,6 +259,14 @@ class Form::Question
     selected_answer_option_is_derived?(log) || has_inferred_check_answers_value?(log)
   end
 
+  def question_number_string
+    if @question_number
+      "Q#{@question_number}"
+    else
+      nil
+    end
+  end
+
 private
 
   def selected_answer_option_is_derived?(log)

app/models/form/sales/questions/ownership_scheme.rb

@@ -6,6 +6,7 @@ class Form::Sales::Questions::OwnershipScheme < ::Form::Question
     @header = "Was this purchase made through an ownership scheme?"
     @type = "radio"
     @answer_options = ANSWER_OPTIONS
+    @question_number = 3
   end
 
   ANSWER_OPTIONS = {

app/models/form/sales/questions/purchaser_code.rb

@@ -7,5 +7,6 @@ class Form::Sales::Questions::PurchaserCode < ::Form::Question
     @hint_text = "This is how you usually refer to the purchaser on your own systems."
     @type = "text"
     @width = 10
+    @question_number = 2
   end
 end

app/models/form/sales/questions/sale_date.rb

@@ -5,5 +5,6 @@ class Form::Sales::Questions::SaleDate < ::Form::Question
     @check_answer_label = "Sale completion date"
     @header = "What is the sale completion date?"
     @type = "date"
+    @question_number = 1
   end
 end

app/views/form/_textarea_question.html.erb

@@ -2,7 +2,7 @@
 
 <%= f.govuk_text_area question.id.to_sym,
   caption: caption(caption_text, page_header, conditional),
-  label: legend(question, page_header, conditional),
+  label: legend(question, page_header, conditional, @log),
   hint: { text: question.hint_text&.html_safe },
   width: question.width || nil,
   **stimulus_html_attributes(question) %>