Welcome to life in the UK.
Recently Newzbin got taken to court (they are in the UK). The thing is, right afterward, someone 'stole' the site code and promptly gave the RIAA/MPAA mob the finger. Newzbin 2 was created.
I can't speak for UK law, but here in Canada, well our privacy laws are worth more to us than the commercial needs of the recording industry.
There simply is no legal method in Canada to prove what I download and when. Not to mention owning the right router renders anything I download indistinguishable noise. I use torrents just as easily as anything else. It's all just a lot of undecipherable unreadable signal.
My advice, let them come to your door first.
Letters in our email, well that says and proves nothing. Even physical mail is not proof of anything. Make them go the distance first.