For the Law exam, you need to be familiar with a number of AICs and the Rules of the Air which are only touched on by Thom (don't know about Pratt) meaning you need to look them up.
I recently bought the UK AIM and, although already out-of-date, it is an excellent reference with the required extra material plus the entire ANO and the Rules of the Air and I would certainly recommend it to help with this paper...
BP