If you do get told to expect a big hold, don't worry. In the early 90's I held for a total of three and a half years between courses and it didn't do me any harm.........Apart from that liver damage thing and a minor dose of the clap.
I'd suggest you don't follow AF's example. If you are put on hold, make the best use of it you can. There are still great courses to get yourself onto, which will be a big advantage later in your career.
I'd suggest that if you are a serious young RAF officer on hold, that you try to get on French courses - and keep demanding them until manning take you off gardening leave. A knowledge of French will be a great advantage over the next thirty years or so.
If you can't get on a French course, then apply for the AACC - that dagger on your shoulder will give you a lot of credibility later in your career.
Even if those options don't appeal, there are loads of other courses you can apply for that will be of great benefit later in your career. And the more courses you apply for and complete, the more likely you are to be selected to resume flight training.