Add a link to help page from the trial mode banner

app/templates/views/dashboard/trial-mode-banner.html

@@ -3,12 +3,13 @@
 
 {% call banner_wrapper(type="mode") %}
 
+  <h2 class="heading-medium">Trial mode</h2>
   <div class="grid-row">
     <div class="column-one-half">
-      <h2 class="heading-medium">Trial mode</h2>
       <p>
         We’ll only deliver messages to you and members of your team
-
+        <br>
+        <a href="{{ url_for(".help", _anchor="trial-mode") }}">Find out more</a>
       </p>
     </div>
     <div class="column-one-sixth">

app/templates/views/help.html

@@ -10,7 +10,7 @@
   <div class="column-two-thirds">
     <h1 class="heading-xlarge">Help</h1>
 
-    <h2 class="heading-large">Trial mode</h2>
+    <h2 class="heading-large" id="trial-mode">Trial mode</h2>
 
     <p>
       When you create a service on GOV.UK&nbsp;Notify, you start off in trial