Lectures are fixed for the whole year in the first year, there are no alternative lectures. You will get one a day for four days a week, and two on one day for the first half of the term, but then that lecture group stops and you have 4 instead of 6 lectures. Lectures are not compulsory.
You get a 5 1 hour tutorials a week, and 1 2 hour seminar. It is possible to attend different ones of these with tutor's permission but i doubt they'd let you do it on a regular basis, especially since you reason is, "I can't be arsed"
Tutorials are compulsory, but effectively, as long as you don't miss 3 in a row they don't mind.
BTW, which unis let you pick and choose your timetable, surely there would be chaos, not know whether you have an empty tutorial or 50 people?