Unless you intend to use the iGP of the 3200G, then it's a bit of waste when you can have 50% more cores, 200% more threads for 20quid extra:
https://uk.pcpartpicker.com/product/mV98TW/amd-ryzen-5-1600-32ghz-6-core-processor-yd1600bbaebox
That assumes they're shipping the 1600AF, which is a 2600 is all but name.
The motherboard is fine, not exceptional - and if you
do end up using the 3200G, you'd need to make sure it's had a BIOS update to support.
Same with the RAM - fine, not exceptional. The CPU is going to play a big factor here. If you opt for the 3200G, it shares the system memory. 8GB is cutting it a bit thin these days for a lot of tasks, and you'd compound the issue if using the APU.
Looks like you're working with a budget of around 200quid?
If so, I'd be inclined to look to something more like this, if using a dedicated GPU:
PCPartPicker Part List
CPU: AMD Ryzen 5 1600 (14nm) 3.2 GHz 6-Core Processor (£93.97 @ Laptops Direct)
Motherboard: MSI B450M-A PRO MAX Micro ATX AM4 Motherboard (£55.97 @ Laptops Direct)
Memory: Crucial Ballistix 16 GB (2 x 8 GB) DDR4-3000 Memory (£69.98 @ Amazon UK)
Total: £219.92
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2020-04-22 20:44 BST+0100
Equally unexceptional board, but does manage to squeeze in 16GB.... for a little bit over budget.
If you want to use an APU, I'd try to find a Ryzen5 APU for the additional cores/threads (only 4/8 on the APUs vs 6/12 on the CPUs), but those tend to get pricey. The 2400G is ~140quid.... the 3400G doesn't appear to be available stand-alone in the UK.... only via Amazon bundles, and they're not particularly great value.
290-320, depending on RAM config:
https://www.amazon.co.uk/ADMI-CPU-Motherboard-Bundle-Graphics/dp/B07TX4JBNZ/ref=sr_1_12?dchild=1&keywords=ryzen+5+3400g&qid=1587584719&refinements=p_76:419158031&rnid=419157031&rps=1&s=computers&sr=1-12&th=1