Unsure what class as it disappeared off my app and log in by the time I landed.

got this from Air NZ tho:

Upgrades requested at check-in or at any of our Lounges are based on set fees, which vary depending on the route and the cabin class you wish to upgrade to. To fully accrue both Airpoints Dollars and Status Points as per the new cabin, the full fare difference between the fare purchased and the best availability on the flight has to be covered. In your case, you will still earn at the rate of the original issued ticket in Premium Economy.