thatbags, They might have had official refreshment times, but teachers get caught up in detentions, meetings, seeing pupils, last minute marking, etc.
I left teaching with a 'compromise agreement'. In other words, the school wanted to sack me, bunged me a few quid and I couldn't wait to do a runner.
The reason they wanted to sack me was that I'm diabetic and they claimed they couldn't make necessary adjustments for me. Diabetes is covered by the Equality Act (the old Disablity Discrimination Act) and they had to consider adjustments. In my case, those adjustments were having a guaranteed snack and loo break every three hours. I wasn't getting them and it was affecting my health - I often felt dizzy and/or light-headed and couldn't work effectively. The school said that they couldn't be guaranteed. There seriously were many times when I didn't go to the loo or have a drink from the time I started until I went home. Quite a number of pupils don't go to the loo during the school day either. I guess we develop strong bladders.
Don't even talk to me about the menopause - it was a nightmare!