There are many great amps out there.
After having gone through a gazillion of rigs in the past, best advise I can give you is to not underestimate the value of a decent cab. I would go 900 quid and spend 400 on the cab. Get an old Marshall (before the 80s and not the ones with G12T75s) - they sound great.
With a head, if I were you, I would look for something with not too many features. 1 or 2 Channels and not much bling bling, the less components in the circuit, usually the better it sounds in a band. More processed tones tend to get drowned out. A JCM800 will always be great. If feature laden is a must, why not get the JVM410 or 205, they are cheap in the UK and sound great, too.