To my earlier list above I'll add a couple more. Just this morning I saw our neighbor heading out, dressed as cute as could be in his tight softball uniform to play a game in the gay men's league (really highlighted his basket, must have been wearing a protective cup).
Naturally in the UK you have lots of team sports, and you can build a men's social group anchored by your team. Which can be gay, or mixed with gay-friendly straights. I can't play team sports anymore but I can watch and cheer for my "team", and then we all go out together for pizza & beer afterwards. I still have friendships I formed that way.
Another one I belonged to might not be to your taste, and not sure how well this might be accepted in Britain: a gay naturist (nudist) club. We had monthly gatherings at all kinds of venues, where we were totally naked. Outdoor picnics and swim parties in the summer at fenced private homes (US suburbia is a natural for that), moving indoors in the winter for dinners, movie nights, or just cocktails with 20 or so guys hanging out (and I mean that in both senses). Or we'd get private use of a bar, or bowling alley, or spa in their off hours
We also participated in parades, naked but with barrels on suspenders (braces) around us, a US symbol of poverty (you have that in the UK?), and staffing our booth at Pride Festivals, likewise naked in our barrels.
And BTW, no sex was permitted during these events, and of course no drugs. If a member so much as felt as guy up he could be thrown out of the club.
HOWEVER, in a wonderful example of double standards, when a house party was over, around 10 or 11, and if the host indicated we were free to stay a little longer as his personal guests outside the official meeting hours, OMG! Orgy time! But not every host did that, and you simply put your clothes back on and drove home, still glad for the company of some really nice guys. Who again, I got to know as friends outside the club.