That's a pity that Croziers no longer sell turkey poults. They were the only commercial producer selling them.
There is the directory at
www.rarebreeds.co.nz but no breeder of white turkeys is listed there. The ones you are after are difficult to breed for backyarders as they need to be artificially inseminated. The males are very heavy and need to be kept away from the food to be able to walk at all.
There are people around who have crossed the large white turkey with the bronze and this gives you a fast growing bird without the problems of the large white.
Where abouts are you? You may have to wait for another month or so and see what you can find on TradeMe.