I'll just say something about the tests that I had to do at the first phase:-
The questions in the written papers were nothing to do with PPL knowledge or physics. They consisted of questions that tested your ability to think quickly within a short time frame. We were told that it wasn't expected of us to finish every one. In my view you couldn't have revised for these tests. The maths that was involved was only very basic fractions and multiplication. There were lots of questions testing your knowledge and understanding of vocabulary. Also there was a kind of personality profile paper with no correct or incorrect answers.
I hope this helps a bit.