Add note to users about frequency of updates

ynr/apps/data_exports/templates/data_exports/data_home.html

@@ -9,6 +9,7 @@
     <p>Although the data is free to use under the terms, we would love to know what your planning to use the data
         and are happy to answer any questions you might have. <a href="https://democracyclub.org.uk/contact/">
             Please get in touch</a>!</p>
+    <p>Please note this data is currently updated every minute.</p>
     <form action="" method="get">
 
         <aside class="ds-filter">