There is an active club in Stevenage
https://www.britgo.org/clubs/map
As @Groin says 6 for a Go club is fine and frankly I’ve yet to go to a club night where this limit would have been a problem! Most clubs are a couple of mates who play Go and call themselves a club…
Plus not long to wait now, 6 will be able to meet indoors from mid May and and 30 outside. So that wouldn’t be a problem. The issue will be about guidance for distance (how far do Go players sit from each other?) and hand and stone sanitisation requirements.