Yellowtriumph....this might help you get to grips with your hub setup...
User guides and manuals for BT Hubs
At the bottom it has a diagnostics gizmo too which could help settle things
But if all else fails, call them and give them what for
(The new Hub 6 is alot stronger wifi signal than Hub 5 and its increased its range too, my phone picks up my Hub 6 from around 500m away whereas on Hub 5 the phone went to Fon almost as soon as I went out the front door)