Do you need to also complete the Australian Travel Declaration (ATD) for arrival back into Sydney from Norfolk Island? The Qantas web site provides a prompt to complete one, but this might just be a default message.
I travelled AKL/SYD last week in J on the QF 787 (Dreamliner) flight. It was interesting to note that the flight featured an 'enhanced' meal service. Unfortunately, the menu was basically the same as the one I had the previous day flying SYD/AKL, which I haven't encountered before.
A choice of still or sparkling water as a PDB is a very poor enhancement in my opinion. The glass of juice, while not the most fantastic option, is a lot more appealing than a glass of water! It did enhance the Business class experience to some extent.