Here's my recommendation(Assuming you already have peripherals).
PCPartPicker part list:
http://uk.pcpartpicker.com/p/CcQbnQ
Price breakdown by merchant: http://uk.pcpartpicker.com/p/CcQbnQ/by_merchant/
CPU: Intel Core i7-4790K 4.0GHz Quad-Core Processor (£270.53 @ More Computers)
CPU Cooler: Corsair H100i 77.0 CFM Liquid CPU Cooler (£87.98 @ Novatech)
Motherboard: Gigabyte GA-Z97X-GAMING 7 ATX LGA1150 Motherboard (£124.99 @ Novatech)
Memory: Kingston HyperX Fury Black 16GB (2 x 8GB) DDR3-1866 Memory (£54.06 @ CCL Computers)
Storage: Samsung 840 EVO 120GB 2.5" Solid State Drive (£58.79 @ More Computers)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£39.95 @ Amazon UK)
Video Card: Gigabyte GeForce GTX 970 4GB WINDFORCE 3X Video Card (Purchased For £0.00)
Case: NZXT S340 (Black) ATX Mid Tower Case (£54.52 @ CCL Computers)
Power Supply: EVGA SuperNOVA G2 650W 80+ Gold Certified Fully-Modular ATX Power Supply (£79.99 @ Novatech)
Total: £770.81
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-04-30 00:11 BST+0100