NAVY Number Plate Surrounds with RNZN ensign are only sold in pairs. The cost of a pair is $45. This is a negotiated deal and includes postage to both Islands direct from the manufacturer. If you wish to change the text the price will rise to $52.95 and you will need to get the Navy Decals separately from Maurice Hartshorne who is on facebook.
The surround manufacturer details are firstname.lastname@example.org , ph 021877016 also on http://www.facebook.com/doozinz