Why are you not considering the standard Sky box? There is no extra fee for this and you can have your Family Pack without the Premium Channels like Sky Movies and Sky Sports.
Also to answer one of your original questions, I would not expect them to sort out the phone line for you, but hey you can always ask!
Don't forget with Sky you get the option of having SkyTalk, which saves quite a bit on phone calling.
On the other hand you can go to BT who will sort out a Sky installation for you....details here:
http://www.bt.com/digitaltv/index.jsp
or a BT line with Freeview here:
http://www.bt.com/btdigitaltv/ed_det...K&obsOID=94262
HTH