this is the cap I've been trying to find most of my adult life. I nearly wept with excitement when I first saw it....and with disappointment when I saw (no surprise of course) that it was a paltry UK 6 3/4 (US 6 7/8, Euro 55). It will probably stretch a size bigger of course (though no promises!)
This cap is WIDE! and it is BLACK! It is NOT multi-panelled but has a single piece top....you see way more of these in old pictures but I only ever seem to turn up the panelled ones nowadays.
I listed it on ebay a while back but got no takers. Here's the link with more pics and description. I will sell it for the start price plus postage. If you are a smaller headed person then this is your lucky day!
Incidentally, there was a good thread about the scarcity of this type cap recently: see here