Probably the simplest thing to do would be to get someone in Australia with a lathe and mill to make you one. Not too much to making one. A lug in the front the major diameter of your bolt lugs milled to the thickness of your lug (that portion about 2" long) then behind the front portion turned down to bolt diameter (I'm guessing .750" in diameter or so here) extending back through the action then mill the back end to fit a socket or a drill a hole in it for a T handle.