Try Bay of islands dive club.
I am not sure how affiliated they are with dive north, however I have been informed that the club does operate separately from the shop.
[url]http://nzu.org.nz/diving-in-nz/director ... islands-2/
I am sure you can get in touch with the club through the shop, the secretary of the club is affiliated to the shop.
Let me know how you get on.
I cant think of anything more relaxing, than being in the downunder, breathing some nice clean fresh filtered 21% nitrox.