While I don’t know this situation, in general it tends to be up to the site to block access, rather than the other way around. If they don’t, some government branch may issue a fine to the server owners, and if it doesn’t get paid it’s seen as a crime committed in the UK. Might mean the fineé gets banned, the country they live in might get an extradition order, or whatever.

Again, no idea about this case in particular. This is just based on what I’ve seen under similar rulings.