New Zealand Irregularly Posted

This is a collecting interest that I am working on at present. It is about postage stamps and labels being used irregularly, and not being accepted for prepaid postage. It includes such items as demonetized stamps, labels, irregular use of official stamps,use of overseas stamps on New Zealand mail, New Zealand stamps being used at USA Antarctica station, and others.
Any collector who has items that fall into this category, I am interested in seeing scans of these for a potential publication. e-mail at lindsay.chitty@xtra.co.nz