Key question still is "WILL THE SECOND TYPE WITH 2 HOLES FIT INTO THE DOOR AND CONNECT UP WITH THE WORKINGS INSIDE THE DOOR ?" - obviously some sort of plate will have to be added behind the second screw/bolt & nut so when tightened up it won't damage the door skin.
Basically I think I have to keep up the hunt for a handle or two to match my "early" handles on the rest of the car.
Interesting to know how many guys have actually had a backplate fracture on these first types - mine only broke when taking the car to bits for the resto. probably took offence at being moved after 60 odd years ?
Here are some photos of the opening in the door for the later type handle, Also detail of the reinforcing plate inside the door. Length of the reinforcing plate is 5-3/4"