The one I got from NZicon came from a collector in Invercargill, the late Bruce Gorton, who was a good pal of mine. Tragically he died young from pneumonia. He sold (or was it swapped?) me a scope pretty much identical to yours, complete with rings, dismounted bases, & leather carrying case. I used the bases as patterns for my late machinist to make up a few sets for keen collectors, but haven't done any for years.

This is a real find. Museum rarity. Good luck with the setting up once you find a rifle; I'd certainly agree with an EFD 1915/16.