$699 converts to £543 but that is before VAT is added. So at MSRP Vega VII should be £650 but lets see what the usual retailer mark up is.
The cheapest 2080 here on OCUK is £650 but my worry is that 2080s are very locked down for overclocking with the Nvidia forced voltage lock. I'm seeing typically between 3% - 10% and that is old Fury X type overclocks and it was slated for being a poor overclocker.
At least Vega has the option of proper voltage control to maximise overclocking potential. I have seen some utter gash reviews from what I can only call moron reviewers overclocking Vega by pushing the core clocks up, or adding +50% to power limit while ignoring the voltage or even the VRAM clocks.
You have to add more than just VAT. There is shipping, insurance, handling, import tariffs, and often additional distributor fees .
Instead of adding 20% for VAT it is more realistic to add 30%.