My first year and second year were both 20 or 21 hours (typically, 14 in lectures, 6 in labs, 1 tutorial). Thankfully, I had only one 9am start. I haven't had my third year timetable yet, but it's going to be a bit skewed, as I'm doing 5 half modules in the Autumn term, and only 3 in the Spring. Subject is Astrophysics.