My kids were asking about Sunday School today - we walked past a Wesleyan Chapel, and that led to me dredging up anything I could remember about the Methodists etc, and it reminded me that I used to go to Sunday School at our local (tiny) chapel as a kid. I think it was held even when there was no service, and the kids attended it instead of the service, when that was on. (We also sometimes went to a bigger church elsewhere sometimes where the kids all marched out 10 minutes after the start of the service to some other buildings over the road, for age-streamed groups doing craft etc.)
I'm sure most churches will still have a children's group on during services, but is it still commonly called Sunday School? Do anyone's kids go like I used to, almost as a social thing? (My parents didn't even attend chapel - they just sent me the fifty yds down the road on my own.)