My build that you could go for:
- PSU: $60/£40 Corsair CX750
- CPU: $150/£95 AMD FX 8350
- GPU: $200~250/£130-150 Sapphire r9 290
- RAM: $80/£50 Corsair 8GB Ram
- Motherboard: $80/£50 Gigabyte GA-970A-UD3
- Cooling: $60/£40 Corsair Liquid CPU cooler H60
- Monitor: $200/£130 BenQ Gaming Monitor RL2455HM (24-inch LED) [awesome monitor, but there are other nice ones for cheaper]
I personally have this build running right now and it was less than $950 which is less than £650 and it runs amazingly well (almost always above 50fps on maxxed settings) playing games like Witcher 2, Battlefield 4, and other games.
Alternatively if you wanted to spend more to get closer to £1000 or change it up somehow, I would suggest some good upgrades to get more out your budget could include: a different motherboard, more RAM, better cooling, a better intel processor like the i7 4790 at $300/£200 (the AMD FX 8350 is kind of a budget processor in the sense that intel CPUs are better but twice the price, also a downside of getting this AMD processor is that overclocking is basically necessary to get good work out of it and you said you didn't want to OClock. Mine is conservatively clocked at 4.72GHz from the stock 4.00GHz. I know some people that have OC'd it over 5.00GHz with better cooling than mine) or you could also upgrade to the Radeon r9 290X for some amazing performances.