Conventional routes are easier to reason about than constraints

app/views/form/page.html.erb

@@ -9,7 +9,7 @@
       <%= page_info["header"] %>
     </h1>
   <% end %>
-  <%= form_with model: @case_log, method: "submit_form", builder: GOVUKDesignSystemFormBuilder::FormBuilder do |f| %>
+  <%= form_with model: @case_log, url: form_case_log_path(@case_log), method: "post", builder: GOVUKDesignSystemFormBuilder::FormBuilder do |f| %>
     <%= f.govuk_error_summary %>
     <% page_info["questions"].map do |question_key, question| %>
       <div id=<%= question_key + "_div " %><%= display_question_key_div(page_info, question_key) %> >

config/routes.rb

@@ -4,8 +4,6 @@ Rails.application.routes.draw do
   root to: "test#index"
   get "about", to: "about#index"
 
-  post "/case_logs/:id", to: "case_logs#submit_form", constraints: { id: /\d.+/ }
-
   form_handler = FormHandler.instance
   form = form_handler.get_form("2021_2022")
 
@@ -15,6 +13,10 @@ Rails.application.routes.draw do
       get "/bulk_uploads", to: "bulk_upload#show"
     end
 
+    member do
+      post "/form", to: "case_logs#submit_form"
+    end
+
     form.all_pages.keys.map do |page|
       get page.to_s, to: "case_logs##{page}"
       get "#{page}/soft_validations", to: "soft_validations#show" if form.soft_validations_for_page(page)