A little while ago I applied to rejoin the RAF and went through the OASC process. (Sadly, I wasn't allowed to even look in the hangar at the leadership tests). Two things surprised me during the day of my visit. The first one was the number of candidates that could not pass the fitness test.
The second was the lameness of the questions during the interview:
"Why did you want to join the RAF?"
"What, the first time round?"
"Yes" ie not "Why should we have you back?"
...and "Do you know what aircraft the RAF operates in the ISTAR role?"
Maybe it was because they wanted my skillset back in the Service, so I got an easy ride!
....So make sure that you can pass the RAFFT!