Have you thought about used? Only asking 'cos I'm in the UK too, and managed to get a JS1000 for £450, and it's a pro quality guitar - check out my review on this site if you're interested.

Also, if you've got a guitar that just doesn't have the tone you want, you might be better off getting a decent distortion pedal - a Boss 'Metal Zone' is a bit extreme, but it's definitely Metal!!!