Iand since neither French or Italian BB threading, i
So is it BSC (British) 1.37x24 or Swiss 35x1 with a LH fixed cup ALA a British/ISO cup? I have to say the stay ends on the Simplex dropouts look way more like "Swiss" than anything British, check out some Mondias while not suggesting this is one (and cannot recall any well-know Brits that typically used Simplex DOs but always have new things to learn!). Sometimes you find a BSC BB jammed into a Swiss BB shell, it CAN fit with some thread deforming! Anyhow I'll be watching for more updates!
One more curveball I'd throw just for grins. consider: "Austrian".