Thanks for your reply. After speaking to a few people we have decided to forget New Zealand cruise as it will be too cold at sea.
Hoping to get a cheap deal on the Millenium repositioning cruise in April going from Auckland to Honolulu.
Go sailing around the South Pacific which we love. Have to forgo the Millenium if so - which is a disappointment.
Will keep searching until the right ship/destination and price comes up.