I went to secondary (State Comp) last decade and we had 30 Mins for lunch (Were not allowed off campus until Sixth Form). It was a split school (Y7-Y9 and Y10-13) and Lunch was staggered, so only one year group at a time.
We also had a 20 Min Morning Break. We finished at 2:50. Clubs took place after School and would finish at 4:00
I went to a different Sixth Form and we had 90 Minutes (this is when Clubs would take place) but finished at 4:00 and only had 10 minutes for Break.
I checked the schools near me:
School A
(Y7-9)
Start Time: 8:45, Break: 10:20 (20 Minutes), Lunch: 1:15 (40 Minutes), End: 3:05
(Y10 & 11)
Start Time: 8:45, Break: 11:40 (20 Minutes), Lunch: 1:15 (40 Minutes), End: 3:10
School B:
(Y7 & 8)
Start Time: 8:40, Break: 10:00 (15 Minutes), Lunch: 12:25 (40 Minutes), End: 3:05
(Y9-11)
Start Time: 8:40, Break: 11:05 (15 Minutes), Lunch: 1:30 (40 Minutes), End: 3:10
School C:
(Y7-11)
Start Time: 8:25, Break: 10:50 (25 Minutes), Lunch: 1:15 (45 Minutes), End: 3:00
School D
(Y7-Y11)
Start Time: 8:40, Break: 11:00 (20 Minutes), Lunch: 1:20 (50 Minutes), End: 3:10
So, does seam a little under (by my area anyway), but not two drastic.