Vatican, not
AFAIK. Apparently the MoD was quite clearly informed that front-line stuff is not possible for the elder Wales (being second in line), and that the charity/representative stuff will take precedence. Hence an abridged course at the RAF. Or at least that's what the Beeb claims. Someone from the RAF was quoted as saying that if it was too short, it would be clear that it was utterly useless, and if it was the full thing without any possibility of him actually using it, it would be a waste of taxpayers' money. Fair dues in that case... they've tried to find a middle way that's allowed him to learn much (and he's a bright lad) in a condensed course.
The younger Wales has found his niche in the TA, he loves doing what he does (being a tank commander), and judging by the interviews, he would probably happily do this to the end of his days, that he knows what his duty is, and that being treated as one of the lads (without all the HRH title drivel) brings a lot of previously not-experienced normality to his life.
Of course, being one of the world's famous kids makes long term deployment just a little more difficult (thanks to the endless tabloid coverage).
S.