https://londonclojurians.org/ is the hub for the London community but I don't know how much is in-person yet. The dojos aren't back up and running yet but I get the impression those will start back up "soon" (ish).

I think the main London meetups are still all virtual: https://www.meetup.com/london-clojurians/events/

I've attended the uSwitch Dojo in recent past, they are in person friendly group working on a small problem for a couple of hours after a pizza and some chat. Highly recommended. I can also see that Funding Circle has now resurrected the in-person meetups (https://www.meetup.com/london-clojurians/events/288023345/) along with the usual virtual ones.