Thanks to Son for his difinitive answer, in his last post, to my last remaining question:

"Why was receiver not marked ZF".

The private seller is reluctant take it back for a refund, so that avenue is not forthcoming. I am not out a huge amount of money, just the disppointment at having hoped to buy a good shooting Enfield, only to find it is not. Darn! Guess I'll have to keep looking and buy again, and then decide what to do with this "museum piece".