Brett dont worry, its just first round, heaps of ppl will drop out at recruiting stage, technically we've got till september till they decide who they want, this recuitment stage takes ages for a reason, to test if ppl really want to do it,
basically they want to best people to do it for them, ie they'd rather take someone who plans to join the adf in the future over someone who just wants to do it for a gap year, because of the white paper they released they've had to be smart about their money in certain areas, and this is one of them. So they want to interview people, then decided if they want them, in the past i think (from what ppl have told me) they took the first in first serve, now they want to see if people are doing it as a 'try before u buy' and not just to say thanks for the money and experience, probablly never see you again kinda thing. i reckon that alot more people will get rejected after thei you session and assessment day because of this fact, so getting this letter doesn't mean anything, if you really want to do it, chances are (even more so this year) you'll get it.