"I shall try to measure some of the blanko SS bayonet blades so that we can perhaps determine the manufacturer."
The inspectors of WaA have rules to accept bayonets, so the measurement of blades are not important here, the special stamping on tang of blade on locking nut, or mashinig spures could be help by deciphering, and only by side by side comparison. But anyway its believed that only the largest producers could realised a larger blanko production. So from this, they are candidates - Hoerster, WKC, Eickhorn,Coppel and probably P.Weyersberg.