It is a bit out of the way for you but The Dive Doctor (The Dive Doctor Ltd) seem to service everything so it might be worth giving them a go. There are other shops in Auckland that would do it for you as well I am sure, but all would be a bit of a drive for youWell, that was fun whilst it lasted... 100 dives last year and time to get my gear serviced, but the only guy servicing HOG in NZ is shutting shop. Found someone who could do them, but they are unlikely to ever hold service kits in stock due to low demand. I must be the only person in NZ using them lol.