Firstly welcome to the forum
To the best of my knowledge you do not need your box connected to your phone line after the first year but would they class this as a new installation and as such start the first year thing off again? Something that may be worth asking them.
I am with NTL and I am happy with it but from what I have heard Sky beats NTL hands down if you want the all singing all dancing stuff with it, NTL do how ever have all the sports stuff that you want.
Now on to BT I wouldn't give them house room, I would rather crawl through a patch of nettles to make a phone call than go back to them but that is just my personal opinion
