Good question! My mum used to take me into Manchester centre to watch one or other of the walks (I think we used to alternate, RC one year and C of E the next) but she didn't work at the time so it wasn't an issue.
I wonder if they had a half-day closing on Friday to accommodate the big RC walks? A lot of places had an early finish on Friday anyway, so perhaps you took an extra couple of hours and made time up on Staurday?
As for the smaller local walks, perhaps they were timed to coincide with the existing half-day/market day early closing arrangements?
I went to a Methodist Sunday school and I think we had a Sunday Whit walk and also a church anniversary walk on a different Sunday, both round the boundaries of the church district. Got a new dress for the Whit walks from Afflecks and that was my best/party dress for the rest of the year!

Barbara