Hi Ian,
I have SEC 5.2 and installed in a distributed installation (the DB on SQL Server 2012). I am yet to configure logging, but there are connectors for Sophos Enterprise Database (2.0 and 3.0) under Node connectors. If you installed SEC in one location, deploy the agent to this server then try the Sophos Enterprise 3.0 Database connector and start it. If you have done like me, you will need to configure the correct DB port and database name. There is a chance that in a distributed installation, it may not allow collection of logs as there is no fields in the connector template to provide authentication details.
Hope this helps.