You seem pretty clued up already tom. Basicly get your mental maths up to speed and swat up on the physics! The rest is up to you really m8, you will either have the aptitude or you won't. Sounds quite harsh but is just a fact of aviation training aswell as a prerequsite of OAT! If you look on the website m8 it give you alot of info about the assessment.
The best personal adive i can give is to enjoy it as there really aint nothing you can do about it! In the interview relax try to speak english, ( i decided to speak some sort of foreign languge, just comes out so easier said than done!). Definetly swat up on OAT and their mottos aswell as current happenings their!
Just enjoy it m8,
Keep it real!
Tommy
ap282