Andrew I think one of the key drivers (from the outside) is Barnbougle, in that the only way to get to KI is by charter flight, so that many will then continue on to Barnbougle - at least that is how they should market it.
We have a trip of 8 going down to Barnbougle with Vortex Air in May - we are going via King Island, play 18 holes at existing 9 holer, have lunch at the pub, and then continue on to Barnbougle - it is almost on the way, and adds little to the cost of getting to BD. ( we are also hoping to get a look at the site for OD preconstruction)