Approaching this one from another angle, does anyone have any details on the relative thickness used in projectiles of differing sizes, presuming that this piece is from an HE shell??
Or indeed does anyone have any opinions at all on it? after all its only hearsay that this was found in the location mentioned, and as much as I believe the person whom I got it from I have been collecting long enough to know that sometimes stories do get added to enhance the price of an item (though not in this case as it didnt cost the earth!!)
Rather than proving that it is from a German Naval Shell, is there anything about it that would suggest it wasnt????