I've got the MadCatz R.A.T. 7 and it's by far the best mouse I've ever owned, incredibly sensitive and completely customisable, also very quiet.
The R.A.T. 5 comes in at around £50, I won't post links, but I'm sure PCS stock it. Look at reviews online, there's a general consensus that this is one of the best gaming mice ever, they're truly epic.
I myself have the Logitech G700s after I broke my G700 from travelling, and it's a great mouse . It feels great, on the heavy side, and it's fairly quiet, at least my gf doesn't complain about it. The battery doesn't really last but I always have it wired anyway so it's not been an issue for me. It also comes in at £49.99. I definitely recommend it.