Google BAE Systems and get in touch. They won't be shy about telling you about the package, given your experience. The cash looks excellent up front, but be prepared for a big culture shock, particularly if you have a wife.
BIG HOWEVER: Network with your Aussie mates and anyone who has been there. It does not suit everyone, the devil is in the detail, as it were. I haven't been there and (probably) never would, but know many who have. Depends on how much you want/need the money.
Having said that, it's not a prison sentence and if you don't like it, you can leave - provided they give you your passport back.