I'm trying to remember what time lunch (dinner) was served when I was in school. I'm pretty sure it was 12 noon. My secondary school had 4 different dining rooms, so there were no separate sittings - everyone had the same lunch period/dinner time, though sometimes it did feel as though we spent much of it queuing! I'm pretty sure we had at least an hour for lunch too, maybe a little longer. Some kids went home to eat, and others to the local chippy. When I was in 6th form we persuaded one of the PE teachers to give up some of his lunch break one day a week to open the swimming pool for us. We must have had at least 20 minutes in the pool to make it worthwhile.
School lunch hours over here are much shorter - certainly nowhere near an hour. Both my kids complain that they don't have enough time to eat all their lunch, though I know part of that is because they spend too much time talking! Still, I was shocked to look at DD's schedule today and realize that her lunch hour is only 24 minutes long. Not only that, but she has 'first lunch' - which starts at 10:48 a.m. Not even time for elevenses and she's having lunch?!