Update using-notify.html

app/templates/views/using-notify.html

@@ -13,6 +13,8 @@
   </div>
   <div class="column-two-thirds">
 
+    <h1 class="heading-large">Using Notify</h1>
+    
     <h2 id="trial-mode" class="heading-medium">Trial mode</h2>
     <p>When you create a GOV.UK Notify account, you’ll start in trial mode. This lets you try out the service, but has some restrictions in place.</p>
     <p>You can remove these restrictions by going live.</p>