Ok, so this may seem like a stupid question but I'm fighting DBeaver and so far it's winning and Google is refusing to pick a side.
I've worked out how to explore the database, view the structure of tables, I can even view the data of a table and filter it.
But if I just want to run an arbitrary SQL statement how do I do that?
And 30 seconds after posting I found the answer. There is an SQL Editor menu appeared at the top of the screen (not in the Database Navigator). Selecting SQL Editor from that brings up a query window I can type SQL into.