The owner of this gun store also produces his own custom rifles and guns from actions he purchases in England. He used to work for Purdey (and a few other British houses if I'm not mistaken). He is currently refinishing (removing scratches and dents where possible and then putting a London hand rubbed oil finish on it) of my Dumoulin. (in the end I didn't dare take a piece of sandpaper to it, no matter how fine, or some chemical to take the oil out. )
So this could be a Ruger M77 that he personally restocked/repaired/etc. (side question, aren't M70's more wanted than M77's for African rifles?)
You mention the stock shape looking CZish, but CZ is more with a hogsback stock I thought (which I do not really like) while this looks more like a straight stock with a cheek comb.
I'm not sure I'll be able to get close-ups on the receiver and bolt, but I can ask about the lineage of this rifle.
Thanks for the info already
@C.W. Richter ! Might have some more questions for you later on!