After reading about some others' experiences I tried again with the second hub.
The hub did eventually connect and the broadband is again working.
Looks like my Hub was put out of action by the firmware update - thanks for nothing BT (not you forum mods, you guys are helpful). But that aside BT are the worst business I have ever had the displeasure of having to deal with.
£50 / month only to be told I have to sign a new contract to replace a Hub that BT have broken ;-D Yeh right, see you later BT, I'm off.