Tetras' advice above is on point.
Maybe speak to OCUK about getting the CPU swapped to a 7800X3D (it's the best gaming CPU right now, period), get the RAM swapped to something 32GB 6000MHz C30 which shouldnt be THAT much more expensive, which is the sweet spot for Ryzen, and take Windows off, and get an OEM key off the net for £10 IF you feel comfortable installing Windows yourself. The £100 you'd save could then be put into the other components
7800XT GPU is a really decent GPU, a bit faster than the 3080 was, just not as good at Raytracing. If there's any budget left at this point, see what an upgrade to a 4070 Super would cost

Only other thing I'd ask is maybe what the cost would be to upgrade that SN770 NVME drive to the SN850X, as its just a bit all round faster due to having onboard memory, but realistically that's last in line as the SN770 is still a good drive!