Mid-high end pc build

Solution
Just saved you from a poor quality PSU and mobo. :)
Little more costly but well worth it. You will not have power issues or mobo failures.
Mobo and PSU are Tier 1 meaning of the best quality and trustworthiness.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor (£178.00 @ Amazon UK)
Motherboard: Gigabyte GA-Z97X-Gaming 5 ATX LGA1150 Motherboard (£99.98 @ Novatech)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory (£41.64 @ Amazon UK)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£32.40 @ Aria PC)
Video Card: MSI Radeon R9 380 4GB Video Card (£178.02 @...
Just saved you from a poor quality PSU and mobo. :)
Little more costly but well worth it. You will not have power issues or mobo failures.
Mobo and PSU are Tier 1 meaning of the best quality and trustworthiness.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor (£178.00 @ Amazon UK)
Motherboard: Gigabyte GA-Z97X-Gaming 5 ATX LGA1150 Motherboard (£99.98 @ Novatech)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory (£41.64 @ Amazon UK)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£32.40 @ Aria PC)
Video Card: MSI Radeon R9 380 4GB Video Card (£178.02 @ Ebuyer)
Case: Fractal Design Define S ATX Mid Tower Case (£57.95 @ More Computers)
Power Supply: EVGA SuperNOVA GS 550W 80+ Gold Certified Fully-Modular ATX Power Supply (£64.99 @ Aria PC)
Total: £652.98
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-07-07 16:44 BST+0100
 
Solution


+1 for this. You want a solid PSU and board. It's worth the little bit extra.
 

SamiSC

Distinguished
Dec 22, 2010
609
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19,360
PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor (£178.00 @ Amazon UK)
Motherboard: ASRock Fatal1ty Z97 Killer ATX LGA1150 Motherboard (£88.02 @ Amazon UK)
Memory: Kingston HyperX Fury Black 8GB (2 x 4GB) DDR3-1866 Memory (£38.95 @ Ebuyer)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£32.40 @ Aria PC)
Video Card: MSI Radeon R9 380 4GB Video Card (£178.02 @ Ebuyer)
Case: Fractal Design Define S ATX Mid Tower Case (£57.95 @ More Computers)
Power Supply: Antec High Current Gamer 620W 80+ Bronze Certified Semi-Modular ATX Power Supply (£58.78 @ Amazon UK)
Total: £632.12
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-07-07 16:54 BST+0100

faster ram, better mobo, and a good quality power supply. and its about within your budget
 

Xemko

Admirable
This will get you better performance:

PCPartPicker part list / Price breakdown by
merchant


CPU: Intel Core i5-4460 3.2GHz Quad-Core Processor (£138.31 @ CCL Computers)
Motherboard: MSI Z97 PC MATE ATX LGA1150 Motherboard (£59.99 @ Amazon UK)
Memory: Kingston Beast 8GB (2 x 4GB) DDR3-1600 Memory (£39.39 @ Amazon UK)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£32.40 @ Aria PC)
Video Card: Palit GeForce GTX 970 4GB JetStream Video Card (£257.96 @ Scan.co.uk)
Case: NZXT S340 (Black/Blue) ATX Mid Tower Case (£49.98 @ Scan.co.uk)
Power Supply: XFX 550W 80+ Bronze Certified ATX Power Supply (£46.18 @ CCL Computers)
Total: £624.21
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-07-07 17:02 BST+0100

Most games are GPU dependent, i5 4460 still very capable/sufficient gaming CPU.
Btw, if you want to overclock that i5 4690k, you need a proper coolant, something like : http://uk.pcpartpicker.com/part/cooler-master-cpu-cooler-rr212e20pkr2