I would do the licensing LONG before 3 years to go. You don't know when the market will change, or when you will REALLY get pissed off with the RAF. Won't help if you get some ****ty job in an out of the way place while you're trying to do IRT or exams and you're nowhere near where you need to be ...... and can't get there etc. Don't put it off, those last few years race by and you could find yourself seriously pressed to complete and apply for jobs. You want to start applying 2 years to 18 months before you exit ........ seriously. Offers don't necessarily come by return of post and you will still have recruiting processes and hurdles to negotiate, and then more waiting. Don't procrastinate!