No clubs that I know of, just various groups that go out riding the local woods.
I think thats what the MSG series and the eastern region MTB league has been set up for nicemonkey..
We do a 15 mile loop most weekends, takes a few bits of road to join up but finishes in old Leigh for a cuppa, always welcome to join us for a sight see, its nothing awesome but a decent ride out…
retro, swap you a tour of our loop for a tour of yours, ridden over Danbury a few times and found some great stuff, but sure I missed a lot.
Other local places that I ride and are good is:-
Throndon (got a great loop there)
Langdon (another great loop there much better than the MSG race loop)