Add duplicate index page content

app/helpers/duplicate_logs_helper.rb

@@ -46,4 +46,8 @@ module DuplicateLogsHelper
     duplicates = user.data_provider? ? duplicates_for_user(user) : duplicates_for_organisation(organisation)
     duplicates[:lettings].count + duplicates[:sales].count
   end
+
+  def duplicate_list_header(duplicate_sets_count)
+    duplicate_sets_count > 1 ? "Review these #{duplicate_sets_count} sets of logs" : "Review this #{duplicate_sets_count} set of logs"
+  end
 end

app/views/duplicate_logs/index.html.erb

@@ -1,3 +1,15 @@
+<div class="govuk-grid-row">
+  <div class="govuk-grid-column-two-thirds">
+    <h1 class="govuk-heading-l"><%= duplicate_list_header(@duplicates[:lettings].count + @duplicates[:sales].count) %></h1>
+    <p class="govuk-body">
+      These logs are duplicates because they have the same answers for certain fields.
+    </p>
+    <p class="govuk-body">
+      Review each set of logs and either delete any duplicates or change any incorrect answers.
+    </p>
+  </div>
+</div>
+
 <%= govuk_table do |table| %>
   <%= table.head do |head| %>
     <%= head.row do |row| %>