Well... talking about cutting it fine. According to the tracking it was only delivered at 12:14pm on 6 November. Three hours later I received a notification from DHL that I have a package coming!
The package arrived yesterday and it was a new (or reconditioned) Perdix AI. It was certainly not the one I sent. It actually looks new but I don't know how to tell. I didn't receive any communications from the service centre, other than the original delivery instructions.
The only cost to me was to ship it to NZ.
I'm happy with the outcome although I will say that I expected not to have to pay to get it repaired. I figured it was either a faulty sensor or the quality of the sensors is not great. Yes, it was 4 years old and I'd done around 500 dives with it but a $1300 dive computer should be able to last longer than that.