I'd say from personal experience that Royal Holloway's Biochemistry course is fantastic, especially if you want flexible course options. Don't go by the ranking this year because it's a well-known fact around uni that the numbers submitted for 2008 review were wrong. Hence the 10 rank drop in one year! Definitely worth a back up place. I declined a place at Imperial for Biochemistry to go to roho so yeah....just my viewpoint
Ditto what people above have said, but they might be a little snooty about grades, or at least demand that you get As in the A-levels in the end. Manchester and Newcastle are supposed to be excellent student cities, no idea about the biochem, but I'd guess it'd be very acceptable
My career helper guy at college tells me Bristol's very good for Biochemistry, if that helps, and I think it ranks quite well on tables.
I can tell you Manchester's a great city to live in, I love it here, and there's tonnes of night-life. My brother says the accomodation on campus is pretty good, and the people are really friendly, though from some of the stories I've heard they're not the most work-minded individuals ^_^"