"Bennett Airtruck (with a c), which looks as though it was cobbled together from miscellaneous parts (which, I believe, it was)."
Thanks to Bill Green's epic "The Aircraft of the World" from 1965, it became the Waitomo Airtruck with a P&W R-1340 and main wheels from a North American T-6.
"When I was looking up the PL-12 in Wikipedia, I had a senior moment with the manufacturer's name, and entered "Panavia Airtruk." "
I thought "Panavia " was a bankrupt South American airline?
Ciarain.