You tossas know nothing about the agreement between the RNZAF and Air NZ, and niether do I. The little I have heard is the RNZAF has contracted with Air NZ to provide flight time for new airforce wings graduates due to the lack of flying available in the RNZAF due to C130 and P3 fleet reduction as those aircraft are in the planned upgrade program.
The reason it went to Air Nelson is that they have a full flight simulator, and the aircraft is a glass cockpit similar to the upgrades on the C130 and P3. Plus being a straight wing TP would be similar configuration to what they are going back to!
This type of training has been provided before in Air NZ, most recently with Jet airways pilots flying the B777, Airwork pilots flying the B737 etc
The Aussies have also done it with
VB and the RAAF before they picked up there BBJ's