Don't let a lack of exposure to UK airspace worry you. Without an IR, you are not going to get in it anyway (besides it is easier in it than outside it!). What really counts is a good grounding in aviation, which the Aussies can give. You'll actually do real nav-exs, right out in the sticks (or the gaffa) and in general, their instructors are excellent. Janadakot also has some nice side attractions such as the Royal Aero Club (I strongly recommend membership), Feemantle, Swan River and the beaches (in Rottnest Island). And what really counts is the JAA licence. Can they deliver? Only you can decide that one.
Best of Luck.
PM