There's the CTC who ride out from either Cott or Humber bridge car park on Sundays, just make sure you have mud guards fitted tho

I rode out a couple of times last year with them, in the slower group. Most were friendly enough & i think most were retirement age. The faster group rides may be a bit younger, not sure, but was warned that if you rode with them & suffered any kind of mechanical problems you would be left on your own, which kind of put me off a bit