to cable forum.
Regarding the so called cap, ntl occasionally write to heavy users, but in the past they will have been going way over the 1GB a day guideline, each and every day. It's some time since it is known that ntl had their last round of written warnings.
NTL's residential broadband services are a contended (shared) bandwidth system. Thus if many users are saturating the available bandwidth it can slow down for all that shares the same connection or UBR. However, many users frequently believe that they are entitled to make full use of their bandwidth, so the P2P users may be behaving, in their eyes, quite legitimately.
Your main hope is that ntl will one day resegment your UBR which effectively redistributes the users and can give more bandwidth.
I'm not quite sure as to how ntl's connections work but, an alternative to try, and if your speed is that slow anyway, you may have nothing to loose, and that is to request a speed downgrade from gold to silver. You may just find that moves you into a range of users who aren't saturating their connections to the same degree, so that conversely you get a better speed of service?
Discussion of capping has been extensively discussed many times on this forum, and is frequently emotive. I doubt the mods will want another thread to start, so do a quick search to see what else has been said.