There are other marks, not clearly shown in the photos. For instance, the marking Mannlicher-Schoenauer changed in it's style at different times. What does it say on this one? "Made in Germany" for instance?

"Not English Make" was long gone before 1960.

Normally the factory had it's name stamped on one side of the receiver and the style of this changed several times in history. Can I presume there's nothing there? Likewise, is there nothing on the upper barrel about mid-way along. It may be very faint. African rifles sometimes have an importer/retailer's name there.