As for the aptitude tests you will get the usual battery of hand-eye coordination etc type stuff plus lots of speed/distance/time type stuff.
Part 1 Consists of Aptitude, medical and Interview. The interview is in two halves, first half is about 25 mins all about you, your background, what opportunities you have had and what you have done with them, second half is about your knowledge and commitment to the military. All about the RAF, its fleet, where it is, why? why you want to be an officer, what makes a good officer etc. You will also be expected to demonstrate a good knowledge of current affairs and from your previous post this appears to be where you should concentrate your efforts. Know about 5-6 International topics of interest/relevance (ie not big brother) and learn all about them. Back issues of the Economist are a good bet in your local library. Know about 5-6 UK topics of interest and do the same with those. If you have a very sketchy knowledge on current affairs you are likely to fail the interview.
Part 2 is to do with group work, lots of exercises challenges and discussions. Just be yourself and think things through.
If you are 23, then you are close to the limit for pilot. You need to be 23.5 ON ENTRY TO TRAINING!!! which means starting IOT. When you say scholarship do you mean Uni sponosorship or what?? Do you know anything about the 24 week IOT course you will have to do, if you dont, find out!
Good luck
DS