As for the repair of your Retina, I suggest you try contacting Paul Barden. He may be contacted at this address
bardenphotographics@gmail.com
Paul is a very competent Kodak Retina repair specialist. He is based in Oregon, in the United States. I expect this will make the challenges of shipping easier for many of you too, compared to sending cameras all the way to New Zealand.
Regards, Chris Sherlock