I’m the next strip of South Downs along from CobraKai and a smidge older, sort of start at QECP and east from there is my knowledge zone. Weeknight group rides cover a wider area.
Saturdays most likely to be found in / around QECP with one or both sons and maybe with a friend or two of theirs in tow.
I think mtbing is harder to ride in groups compared to road and even gravel, as you not only have people with differing fitness levels, but also off-road riding skills.
We have a bit of this in our Tuesday group. The benefit of the South is the technical skills bit really only shows in 20/30 second waits at the ends of bits of Singletrack or downhill and the fitness by a minute or two on the climbs.
I think it really depends why you ride. I want to enjoy riding and good company. I don’t mind stopping to catch my breath for a few minutes and a quick chat. If that’s the group dynamic then it’s great.
On current fitness I think I’d hate group road riding though. Not fit enough on the flats and ups and not confident enough descending to group ride, although it’d probably do my fitness good.