Thanks for your replies.
Yes I have read through my contract extensively (as I have been offered a place to start the course in the near future) and forgive me for being a touch pedantic but the exact clause you are talking about says that you are not allowed to be employed or carry out any other work during the time of your agreement "without the prior written consent of APL".
Is it the case that no one does any weekend work then because they are reluctant to ask CTC/APL for written approval of it?
I imagine it wouldn't go down greatly to ask for this anyway?