I always thought it was the law that tea time was 4 pm. When I was at work, the tea trolley was wheeled past my office at 4 pm. Everyone would then meet in the Common Room for a cup of tea and a slice of cake.
When my children were young there were a few cafes near the primary school that didn’t open until 10.00. I always thought they were missing out on custom from people dropping off children who may have liked to meet friends for coffee before going home.
I know the one I often go to clears up by 4 and the lady that runs it doesn’t have children and most of the staff are teenagers I guess with an hour clearing up that is a 9 to 5 day, then the pub grubs take over They do do lovely cakes and scones but think they are bought at all times of the day
I am currently staying in a lovely small town which attracts many visitors. It has many restaurants and cafés, but none will be open after 4 pm. It is not just Sundays: most cafés, especially those which are actually part of tourist attractions or in touristy areas, seem to close early, just at the time when you are ready for a cup of tea. I know staff want to get home, but it strikes me they could be more flexible in the sort of places that attract visitors.