Query Explain Plugin: Connection error: Access denied

I have anemometer set up on two ubuntu servers.
One server is the apache server and the other is the database server.

I'm trying to use it to look at a Moolde install.

I have added the global_query tables to my moodle database and used pt-digest to pull in the slow queries. I've set the config in anemometer to connection to the database server and database

Anemometer connects to the database and shows me all the slow queries. When I click them to see the details it shows me the graph and the queries that were run. However the explain part gives me;

Error in Query Explain Plugin: Connection error: Access denied for user 'dbuser'@'10.0.100.52' (using password: NO)(1045)

100.52 in the local ip of the apache server and not the remote database server - so it's not surprising that it doesn't work.

How do I set this connection to be the correct database please?