I've been playing guitar for a couple of years and I've decided to get rid of my starter stuff. Here's some info to help you to advise me.

I have very limited knowledge about guitars, amps, pedals and such.
I play rhythm guitar in a metal band influenced by the likes of Lamb of God, Trivium, Machine Head, All That Remains and Parkway Drive.
I just bought a Peavey Valveking 212.
I don't want to spend more than £500

ltd stuff in that price range really doesn't leave you alot of decent options imo unless you were willing to spend a bit more but anyway i've just picked out a few from gak and here they are

http://www.guitarampkeyboard.com/en/70538 overbudget but imo still worth it

hopefully one of them appeals to you