Just been on the Web chat for an hour with a completely unhelpful chap where I am also seeing strange behavior from my Smart Hub - its only able to sustain one stable connection. Eventually the chat randomly ended when the agent ran out of excuses. Poor show BT.
If you haven't already done it, make sure you turn off "smart setup" on the Smarthub.
See link how to do that.
http://bt.custhelp.com/app/answers/detail/a_id/44328/~/what-is-smart-setup-on-the-bt-hub%3F-how-can-...