i play mostly 80s metal such as megadeath, metallica, g n r, motley,

then some country/folk on the side.... and rock/pop such as beatles....

looking to spend 250 gbp max and it must be able to do small gigs too.

suggest me an amp!
Peavey Valveking. Give it a speaker swap and you're set.
I don't know what to get if you want more gain straight out of the box though.
If you were to buy a Peavey Valve King, and then possibly throw a stomp such as a TS808 in front, you might be able to push it into higher gain territory.