On the topic, is Legal Studies 3/4 difficult to pick up on for students who have missed Unit 1? I'll be able to swap into the Unit 2 class but I've been told there's some relevant stuff in the Unit 1 that I've missed out on.
If it's largely the parliament, I think I've covered that well enough in Politics but I know nothing about courts.
nope, never did unit 1/2, got 50

you really won't miss out on much if you go into unit 2. maybe some definitions here and there and the court hierarchy, but easily made up for (just get a quality 3/4 study guide and flick through/read in your free time)
as long as you work really, really, really hard on unit 3/4, you won't be disdvantaged. you'll probably only be slightly behind for the first 1-2 weeks, but come revision/exam time, you'll be just as prepared as the people who have done unit 1/2.
personally I prefer not doing units 1/2, but that's another story..
good luck!