You'll be able to do the TAB (tote) on the day. I have friends and family in Australia but it's a flat handicap ffs!
Just my view but I think that Vauban's improvement on the flat is over-rated because of the time between his flat runs in France and then at Ascot. That sort of improvement is perfectly natural between 3 and 5 and is confirmed by the NH rating of 160. Using the 45lb formula makes his flat rating 115 so just about right. If he'd been on the flat in that period rather than jumping I'd be fairly confident that he'd have improved by roughly the same amount and don't really expect him to have that much more in him. This far out, 4/1 is really very poor and complete lemming fodder.
If I was to have a bet, which I certainly wouldn't be doing until at least the next forfeit stage, I'd be looking at a horse who has been mapped for this all year, is already qualified, has a light weight, is in the right stable and, crucially, is shorter in Australia than over here. Step forward Goldman.