Robin,
I know your skull. That is why I said, it could be interesting for some other collectors. My first thought was the same.
It looks similar, but I think the skull in the picture has a jaw. And your skull is a jawless skull. But who knows? Maybe only "künstlerische Freiheit"?
Look at the skull of the Brüssow Freikorps! Unusual picture, I think.
And I could say, my skull is comparable to the armshield next to the Reinhard badge! Not the same, but similar.
Looking for answers is a part of the hobby. It is a fascinating hobby, isn't it?