I would go with this.
PCPartPicker part list:
https://uk.pcpartpicker.com/list/dGw84q
Price breakdown by merchant: https://uk.pcpartpicker.com/list/dGw84q/by_merchant/
CPU: AMD - Ryzen 5 2600 3.4GHz 6-Core Processor (£151.19 @ Aria PC)
Motherboard: ASRock - B450 Pro4 ATX AM4 Motherboard (£94.67 @ More Computers)
Memory: Patriot - Viper 4 8GB (2 x 4GB) DDR4-3000 Memory (£80.28 @ CCL Computers)
Storage: Crucial - MX500 500GB 2.5" Solid State Drive (£76.79 @ Aria PC)
Case: Phanteks - ECLIPSE P400 ATX Mid Tower Case (£51.59 @ Aria PC)
Power Supply: Corsair - TXM Gold 550W 80+ Gold Certified Semi-Modular ATX Power Supply (£67.99 @ Amazon UK)
Total: £522.51
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-08-01 19:49 BST+0100