Hi Roger,
I have a similar collection of photographs in my possession. The car line up in post 5 is according to my copy the clubs very 1st run. Your print is reversed I see , the cars are all lh drive.

Your uncle Eddies Morrie 8 is the 2nd one in on your right. That’s also him in the mud climb. The other two are Ralph Watson (Singer 9 LeMans) and Ken Hemus Sunbeam.
Looked like good clean fun from a great era of NZ motoring.
I see I have several shots of the Brown Ford 10 special at Seagrove Airfield also.