Well if going that far one could also block accept-langage in Nginx of languages from the UK not saying anyone should, kindof a jerky thing to do. Does not mean they are physically in the UK at the moment but they may return from whence they came.
# rudely drop browsers that include the languages from Britain, Scotland, Ireland
if ($http_accept_language ~ (en-GB|gd-Latn|ga) ) { return 444; }
There are probably more that would need to be included [1] Instead of dropping with 444 one could give a 403 with a terse and hopefully polite error message.
[1] - https://learn.microsoft.com/en-us/graph/search-concept-accep...