This may be the last time I post on this, I'm getting a severe attack of de ja vu!
I think the photos prove Nike was wearing a AGV X1 in Germany in 1976!
Merzario found the helmet lying in Niki's lap after the accident.
Merzario also picked up the helmet after the ambulance had left the scene, and showed at least three other drivers that the strap was still done up.
There was no catch fencing at that particular spot to remove the helmet.
It was retained in the cockpit by the medical air pipe.
It was a single shell size, and the use of over thick padding was proven to have contributed to it coming off.
Indeed, one of the tests you were told to do when buying a helmet was to put it on, do it up, tip your head forward, and try and pull the helmet off by grabbing the back by the nape of the neck, exactly what happened to Niki's, as Mike has pointed out.
My observations of the padding was that if it was moving around, even though the helmet felt way too tight, there was something amiss with the way it fitted.
It is a known fact the strap was originally located too far forward.
So in summary, quite a lot of facts.
A final point, in all my time working for Bernie, and attending Grand Prix, I came into contact with Niki a lot, and interviewed him on many subjects, including his accident. He didn't sue as he was being paid an enormous sum by AGV, the fact he saw the season out with a helmet he knew had contributed to his injuries says a lot, but believe me, he knew, and as I have quoted, he has said to me, "if I had been wearing a Bell, I wouldn't look like this". No conjecture, no guess work, and I stand by my opinion that it is a crucial part of the story, because IF Niki had been wearing a Bell, would he have even gone to hospital, and if he hadn't would the season have gone down to the wire, etc etc etc