Well, as I'm sure you know if you work anywhere near NTL's retentions department, there's published offers, and there's what you can actually get out of them if you threaten to leave.... I cut my teeth at this lark years ago with Orange, way before there was any such thing as formal handset upgrade policies and you had to fight to get a new handset on your existing account for something less than about £300. The fact is, if you make enough noise, they will do you a deal. Personally, I would try your hardest to get a deal off them for your existing account before trying to sign your gf up instead ... I recently signed up with $ky as a new customer and they asked some pretty direct questions about whether I or my house had ever had them before.
You have nothing to lose ... be firm, but always polite.
