Essex & Portsmouth are rumoured to be good- I attended Essex University in 1998, and the computer courses there were pretty good. Plenty of labs, decent equipment, and although the buildings there are a little dated, the content, I found, was well thought-out and interesting.
The reason that Essex is supposed to be a good University is that they drop all the courses that don't "perform" well, leaving high-scoring courses behind

Computer Science has been there a while.
Portsmouth is also supposed to be a good Uni, but I haven't been there myself. Lastly, I remember UEA (University of East Anglia, Norwich) being a good computer science Uni when I visited.
Hope this helps
