They are price at $359 and $259:
https://www.techpowerup.com/282800/amd-announces-ryzen-5000g-and-pro-5000g-desktop-processors
So it should work out at approximately £300 and £220,if you include VAT and current exchange rates. Changes over the CPUs include a reduction in L3 cache to 16MB abd 24 PCI-E 3.0 lanes instead of 24 PCI-E 4.0 lanes. Essentially these are the Ryzen 7 5700X and Ryzen 5 5600 non-X in the range for now.
If this is the approximate price for a 5700G (£300), then count me in. I'll keep an eye out for this. Does OCUK have pre-order notifications by email once expressed an interest?