Chris,
This is becoming a minefield and the comments above don't help.
The copyright laws in New Zealand clearly give the photographer copyright to a photograph, unless the photograph was commissioned by another, who then is the copyright holder.
A person who is not the copyright holder can display another's photograph, for example in a gallery, but may not post the photograph on the internet, as this involves copying of the work.
The law also states that copyright is infringed when a person does something to a work in a way that is reserved to the copyright owner, unless permission has been granted.
As for the argument of British vs New Zealand law, this is irrelevant as both countries are signatories to various international conventions. Pretty much the same rules apply, regardless of where you may be in the world.
The law in New Zealand specifies that, if a person wants to use a work in any way that may infringe the rights of the copyright holder, then the copyright holder can grant a licence to use the work in specific ways, and a fee is usually charged for that licence. (only 'usually', not obligatory).
Two problems arise here:
First; when a viewer sees the thumbnails on this site, there is a clear copyright notice at the bottom of the thumbnail. So, regardless of what one may write in the accompanying description etc, the initial view states quite clearly that the copyright belongs to the poster.
Second; As you have received a lot of negatives from Jorgen Lohn and there has been a lot of controversy over what he actually owns in terms of copyright, getting permission from him may be worthless.
You could therefore quite innocently post a photograph, thinking you have the appropriate permission. The original photographer may later see your posting with the copyright being attributed to yourself and that could get both yourself and the site into trouble.
As I said; it is a minefield but the major problem does seem to arise from the posting on the internet which is seen as 'copying'.
I suppose, in a way, the site itself has some liability too.
Click on a photograph and at the bottom left corner is the label 'Photographer'.
It would be more accurate and less controversial if this label was to read 'Poster'.