The selection is run by Bond Aviation, not Astraeus, and consists of an interview, some written psychometric tests and a sim ride.
Just be yourself in the interview, as for the written tests, well they're meant to look at your aptitude, I believe there are some books you can get to help prepare for them, not sure what they're called though.
For the sim make sure you are in current IR practice and that your scan is up to speed.
All the best