I think the get a number of details wrong in this story.
Dunstan lives in Victoria, not New South Wales (his farm is near the border).
http://gunwatch.blogspot.com/2017/09/australian-gun-culture-part-26-guns.html
Everything I’ve seen about this says he lives in Bungowannah, which is in New South Wales - only just but definitely in New South Wales.
It matters because I think he’d be better off if he lived in Victoria - NSW Police take a harder line on the rules concerning firearms storage than Victoria does (his wife knowing where the key was is a potential problem in New South Wales - it wouldn’t be in Victoria).
I’m pretty sure he’ll get his firearms back and keep his licence in the end - it’s just likely to take two or three years for the court process to be followed. That’s one of the biggest problems here - even when the law is on your side, it takes way too long to get a decision. Local police should be allowed to exercise common sense on this, rather than have to take it to court.