If you're using cloudflare you can block counties via that.
I'm also in the UK and run an instance - the problem is that the guidance is too large and overbearing. The stuff that actually mattered hadn't even been released by OFCOM last time I bothered looking, such as the risk assessment.
I guess we'll know more when they release the guidance on age verification - that will be what kills most sites off if they insist its required for all social media