AlexanderB -
People who have logged over 20 hours do the advanced course. Although I think this might need to be 20 hours of powered flight. Either way you should be right.
MudRatt -
When I sat my OSB (earlier this year) I wasn't employed. I had worked throughout high school and college and for the next year (Uni) I hadn't worked at all. It wasn't even mentioned in the interview though.