50 questions: a good half of it is about JAA Performance stuff ATPL. So concentrate on performance jet airplanes. Forget the turboprop stuff. And the rest is more or less basic pilot knowledge.
I think if you study FAA perf stuff, that should be ok as well.
Be relax and yourself during the interview. Do not try to invent things that happened to you. But be ready to answer questions with real examples. They like examples. If no examples pup up in your mind, just tell them, and they pass to the next question. But have real examples in your pocket as you can not go all the time to the next questions.
Good luck