Solved! Go to Solution.
They are coming from your hub - both used to be called BTOpenzone and BTFon - they are basically the same when coming from the homehub - yes there are now technically 3 wifi connections from your hub.
There have always been two extra SSIDs but, on my hub at least, they don't always both show at the same time or they may have different signal strengths. I assume that separate connections are necessary for non-BT Broadband customers, who can obtain access either by subscription to BT Wi-Fi or by joining the Fon network. A BT BB customer can connect to either.