I know this is an older thread, but I came across it and felt the need to add a comment... Most companies I know use NZ Post for Waiheke, Gt Barrier, Chatham's and Stewart Island, because to their credit, they do not charge any extra and the delivery service is reliable.  You do not need an account with them (although it is a bit easier if you do have one as you can book now and pay later) - and you can easily use the "Send It" feature (https://www.nzpost.co.nz/tools/send-it/nz) to get a ticket cost, print the ticket and book the pick up all in one place.  I have found it very very useful i...