In our old (1928) prayerbook (I'm Episcopalean) there used to be a prayer that started:
"Almighty God, who desireth not the death of a sinner, but rather that he may turn from his wickedness and live..."
I can't do much more for y'all from here in Texas than dig out that old prayerbook and pray that prayer over Mr. Corbett.
Be Loud, be Proud. Complain to all levels of gov't, break down the different departments concerned and press them about the particular-to-them-each features of the situation. Is there a "class action suit" provision in Aussie law?
You'll have to look each other in the eyes and say, "This may take a while. We are in it for the long haul." And make plans to share the steady pressure at all levels. Give each other time off once in a while--slow response can engender depression. Keep tissue available for those moments of frustration when tears of anger/sorrow flow. Recognize you've taken on a lifetime battle--maybe have to pass it on to your kids. Keep each other encouraged.
I'm just a dumb Texan and know zip about your gov'tal structure. Besides the Prime Minister, you've got governors of each--um, state?--national departmental sec'ys, regional departmental heads--this is all guesswork. Don't be sneaky/nasty(energy waste), but STEADY, UBIQITOUS, PERVASIVE, PERSEVERING. And keep up the music.

But you already figured all this out and that's why you're feeling desparate, I guess. Wish I knew more to tell you. Keep praying. Tw