Use govuk_back_link helper

app/views/devise/passwords/new.html.erb

@@ -1,5 +1,8 @@
 <% content_for :before_content do %>
-  <%= link_to 'Back', :back, class: "govuk-back-link" %>
+  <%= govuk_back_link(
+    text: 'Back',
+    href: :back,
+  ) %>
 <% end %>
 
 <%= form_for(resource, as: resource_name, url: password_path(resource_name), html: { method: :post }) do |f| %>

app/views/devise/registrations/edit.html.erb

@@ -1,5 +1,8 @@
 <% content_for :before_content do %>
-  <%= link_to 'Back', :back, class: "govuk-back-link" %>
+  <%= govuk_back_link(
+    text: 'Back',
+    href: :back,
+  ) %>
 <% end %>
 
 <%= form_for(resource, as: resource_name, url: user_registration_path(), html: { method: :patch }) do |f| %>

app/views/form/page.html.erb

@@ -1,5 +1,8 @@
 <% content_for :before_content do %>
-  <%= link_to 'Back', 'javascript:history.back()', class: "govuk-back-link" %>
+  <%= govuk_back_link(
+    text: 'Back',
+    href: 'javascript:history.back()',
+  ) %>
 <% end %>
 
 <%= turbo_frame_tag "case_log_form", target: "_top" do %>

app/views/users/account/personal_details.html.erb

@@ -1,5 +1,8 @@
 <% content_for :before_content do %>
-  <%= link_to 'Back', :back, class: "govuk-back-link" %>
+  <%= govuk_back_link(
+    text: 'Back',
+    href: :back,
+  ) %>
 <% end %>
 
 <%= form_for(current_user, as: :user, url: account_update_path(), html: { method: :patch }) do |f| %>