Thanks for your help!
The system I have decided on is here:
https://uk.pcpartpicker.com/user/psoxs/saved/Qt8wP6
PCPartPicker part list:
https://uk.pcpartpicker.com/list/pL2hxY
Price breakdown by merchant: https://uk.pcpartpicker.com/list/pL2hxY/by_merchant/
CPU: Intel Pentium G4620 3.7GHz Dual-Core Processor (£89.99 @ CCL Computers)
Motherboard: Asus PRIME B250-PLUS ATX LGA1151 Motherboard (£78.57 @ Amazon UK)
Memory: G.Skill NT Series 16GB (2 x 8GB) DDR4-2133 Memory (£100.90 @ Amazon UK)
Storage: Seagate BarraCuda 1TB 3.5" 7200RPM Internal Hard Drive (£37.99 @ Aria PC)
Video Card: Gigabyte Radeon RX 480 4GB G1 Gaming Video Card (£153.54 @ Aria PC)
Case: NZXT Source 210 Elite (Black) ATX Mid Tower Case (£41.39 @ Aria PC)
Power Supply: EVGA SuperNOVA G3 (EU) 550W 80+ Gold Certified Fully-Modular ATX Power Supply (£78.24 @ Aria PC)
Total: £580.62
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-04-05 12:46 BST+0100