Lol, I could get it as far as Winchester for you but that would be it. Well worth the 2 hour drive from your end imo
By the sounds of it you are looking for an aggressive hard tail so really with 120mm to 150mm suspension travel and some decent widish tyres 2.2-2.35. You could cope with a 100mm fork if it is well rebound damped and the frame geometry is more relaxed (head angle approaching 71-73 degrees compared to a cross country bike head angle which will be in the high 60’s). If you go for an older or well used bike you can blow your budget on refreshing the odd drivetrain part or a suspension service (mid to higher end forks can cost £80-£150 for a service if they have been neglected) etc, unless you get very lucky and it has been kept in a garden shed all its life or just had a full service.
When I bought my GT last year I was in the same position looking for exactly the same type of bike. The laugh is I only used it for pootling up and down the beach front in the end. I looked at everything in budget and in the end upped my budget to £600 to get the GT new. I gave up trying to find second hand as a lot of the auctions said one thing and when I went to see the bike, they all had issues, damage etc.
Your budget really limits you to a handful of bikes in your price range worth looking at and I would consider the GT Aggressor XC1, Carrera Fury or Genesis Core 10/20.
The Aggressor XC1 is actually a really good choice of bike as long as you get the last version they did circa 2010 (I got mine last year in Halfords end of line clearance). Its got some good kit like the Deore SLX rear mech and Deore Front mech and shifters where bikes like the genesis only have alivio and possibly a Deore rear. Not only that but you get a great Marzocchi Bomber fork. It is basic but has the usual ultra plush Marzocchi damping and because it is coil sprung and not air and has a sealed all in one compression unit, maintenance is nominal. It is a much nicer fork than the lower end 120mm Rock Shox and Suntours etc.
You could get a cheap Carrera or Cube or any other cross country type of bike but it really doesn’t sound like the sort of riding you are going for and if you get it wrong you won’t enjoy the cycling as much.