When Will You Hear
This is only a guess, but my theory as to why some people get confirmation very quickly and some take a while is wholly down to how you scored. If you score very well on the tests your in and there is no point delaying letting you know. If you score badly your out, so again, no point dragging out your anxiety. If you score to an acceptable level, they will hold off letting you know because other higher scorers may come through in later tests that could potentially knock you out. So no news is good news as far as I am concerned. You can't do better than your best in any instance, so if you do get knocked back at least you can take comfort from the fact that in 3/5years from now when your on a plane somewhere over the UK, you know the person controlling hasn't blagged their way in and that you are in well trained hands.
So in summary. lets say there are 500 (pure guess) places at the next stages, if you haven't heard, I'd say you're in one of those places, with the caveat that you could drop off if more high scores come along.