Heck, the Brits and Kermits even go halvsies on carrier(s).
yitbos
It is a little further advanced than that. In service: Italy, Netherlands, Norway, France.
Basically it came to going for a heli tailored to Aust needs or go the MacCopter and hope it covers what comes up in the next 20 years.
With a risk averse government and a number of recent failed projects they went with the decision least likely to cause future embarassment to the politicians.