I have now been shown photographic proof that the James Aviation sigwriting was indeed present under the starboard wing at some stage in its active life.
Fair enough. Live and learn.

Presumably Fieldays is not an airfield?

The Fieldays site at Mystery Creek is a rural property located just a short distance from Hamilton Airport.
It’s prime function is to hold the annual four-day Field-days agricultral show, which attracts over 125,000 visitors not only from the New Zealand farming community but also from around the world.
The site also operates as a function and exhibition centre at other times of the year.