I got a couple of sets done a few years ago , I got a set which is just a duplicate of the issued plates but in euro form and another set which is just for show at car meets and is never used on the road.
They were the same as the nz ones (done in Germany). The picture is of the ones just for car meets.
Both sets cost somewhere around $40 nzd from memory.
So yeah PP have a complete monopoly in NZ , I think there has been a few people try and challenge this but hit a brick wall straight away with the NZTA.
