Far as I know, New Zealand has a history with these things. Didn't they get something on a TV camera in the 1970s? And I guess your type of sighting, a nocturnal light that doesn't quite behave like a star, meteor, airplane, helicopter, satellite, chinese lantern... should be the most common one. Still, lucky you
If I see a light moving in the night sky, I always think, if it doesn't do something unusual it's just a satellite etc. On one occasion, there was a little zig-zagging, on another (with telescope) it seemd to make an abrupt turn. Yours did the right angle turn too, so I guess there is a good chance you saw a real unknown.Anything else that was unusual? Acceleration etc.?
Keep watching the skies.