Thanks Clive, it would really help a lot.
Oding, I took some photos of my 80's ambulance doors and sadly, I don't think they will be of much help.
The locking and closure retaining system looks to be quite different.
Facing the back of the truck, the larger door is on the Right Hand Side, and that has a simple (reddish colored) rubber stop mounted side by side with the retaining catch, at the top of the frame (truck body) as seen in this photo...
Directly below, at the bottom of the frame (truck body) is a rubber catchment bracket next to the retaining catch...
And on the door, to align with the rubber catchment, is this... (Note, the bracket with the hole in it on the right should have a rubber stop in the hole, but it's missing)
The horizontal bar, when the door is closed, fits tight into the "V" groove of the rubber, limiting vibration vertically, and the plates each end of the bar fit snugly either side of the same rubber catchment, thus limiting lateral movement under vibrations.
The smaller of the two doors (on the Left Hand Side) has nothing in terms of an "anti rattle" device, it sits against a heavy rubber surround (which is mounted on the larger door) and just has the single catch mechanism that locks against the larger door.
Let me know if any other views might assist. Sorry if this is not much help.