I dont think you will have any luck with records search in NZ ..Others have tried it and failed
David Hayward will help you with the SM contract details ... he is usually lurking around this forum ....DAVID HELP
Having a British Z number means it probably was issued to NZ forces in Nth Africa or Italy . Its a rare vehicle in NZ , consider yourself

lucky
And, keep away from these critters

We know how you guys react when Sheep are involved , it's hards to control yourself, but please try.
MIKE