I think if you are just a heavy downloader then ntl will not bother you. I think it's when you start to upload constantly that ntl might give you a call as I'm lead to believe that it is the upstream that affects the network more than the downstream. Why do you think they only give 256k, if you want more then you have to pay alot more.
With regard to the filesharing issue, I knew someone that was downloading movies using bittorrent and was subsequently issued with a threat of legal action by universal studios. It had his name, isp and movie and looked pretty legit. Did a search on google and I couldn't find whether or not it was a hoax. I read that the RIAA (Rip-off Industry of American Association) only target those users that heavily share the files so if you don't act as a server and allow people to download from you, I reckon your pretty safe.
The trouble with file sharing software is anyone can see exactly what you are sharing. Download from the newsgroups, it's more anonymous and afterall, you are only downloading text headers
