As with many other subreddits, /r/LegalAdviceUK (which had been dark since the start of the blackout) has been sent a thinly-veiled threat by Reddit.
So they’ve reopened in order to start moving the entire community of 810,000 subscribers to somewhere else.
As you can imagine there are a number of legal professionals who moderate that sub, and they really don’t take kindly to being threatened. They sign off their reopening message with “Fuck /u/Spez and long live John Oliver.” but for the real fun you might want to look up a very famous British legal case they reference, Arkell v Pressdram 1971.
For what my 2c are worth, I think legaladviceuk is probably the clearest in terms of discoverability. Despite a community existing on a UK-focused instance, it’s ambiguous as to whether it’s UK specific.
In the end though, it probably doesn’t matter too much, as long as the instance is being actively maintained and is in tune with the values of the community.
Setting up your own instance would actually probably be the best idea but if there’s no one technical around to maintain it I’m not sure it would work out.