Finally back here again, with a few things on my conscience:

-will get back to you soon, Bwana338, although likely this rifle went to India rather than Africa, but who knows? It certainly appears to have had a busy life!

In the meantime, Paradox has kindly sent me a pic of the rear scope base photographed from the top. It explains the four holes in the rear bridge of my example, additional to the 2 new holes for the modern bases.

Soon to chat with pjaln as well, my time has not been my own of late. Very much looking forward to building a rear mount that duplicates the original and effectively covers all 6 holes in the rear bridge!
Hopefully I can get back onto this early in the New Year.

Thanks to everyone for your help and encouragement.