Want a new amp - 100 watt + - preferably a stack, good metal sounds to compete with other guitarist in band who has a stupidly loud amp? xD
Metal/Heavy Rock, going for something similar to Randy Rhoades sound. Cab and Head included in price.

Thanks for any help.
Jus thought I'd say - I have the same amp + very similar guitar to you :O (Washburn) OSSUMZ Thanks also I was thinking about a Marshall, and the Pre-Owned idea ain't bad.
You won't need a 100 watt valve amp. You won't even need a 50 watt one unless you practise with an enormous PA and have the drummer mic'ed up into? I know your guitarist may have a "huge" amplifier, but if he doesn't crank it—which I doubt—you won't need a big amplifier to “match” it.

That said, Bugera offer a solid range. 333XL, 1990, 1960, 6262—I can only vouch for the latter of the four, the 6262.
It's essentially a Peavey 6505 clone which is then based off another amp, a Soldano SLO 100, I believe. Which means it has high amounts of liquid gain and the option to scoop or bump your EQ in any way possible. I noticed a couple of dead tones in it, unlike it's more expensive counterpart, but that's what you are to expect for a 120 watt valve amp under £500. And because of that, also, they have been known to break down. But folks in the Bugera Thread will know more on that. I've only experienced one breaking down in my personal life. It belonged to a guy I know. His was the 6262 I tried out.
Anyway, back to the sound... it's full and bassy with more crystalline punch than the Peavey 6505. It's less rugged and raw, more refined—maybe more compressed and more British sounding than American?

Other than that, you have the Peavey Vypyr Tube 60, Line 6 Spider Valve, possibly the new Peavey 6505 60 watt 1x12 when it comes out, or a Randall RG 50-TC?

There may be more to offer through the used market...