The following would be a good gaming build, I'd see if Scan can build it and overclock the CPU and GPU for you for under £700. If not you could do it without the SSD.
AMD Athlon x4 860K
8GB (2x4GB) HyperX DDR3 FURY Blue 1600Mhz
MSI A88XM-P33 V2
Crucial MX100 250GB
1TB Seagate ST1000DM003 Barracuda
2GB Sapphire Radeon R9 380 Dual-X OC
620W Seasonic S12II-620
Fractal Design Core 1300
Cooler Master Hyper 212 EVO