Re: "The rifle would have been first proofed in Vienna and then reproofed in England. NPv means Nitro-proof Vienna. The Austrian proofs are probably mostly hidden inside the stock mortice along with the year of manufacture. Something like 656.23 will mean the 656th rifle proofed in Vienna in 1923, for example."

The only marks on the metal inside the stock are a +1,a V in a circle and a T in a circle, all three on the barrel and the serial numer (213), -1, a T in a circle and a very small K in a circle (double stamped one on top the other)on the action itself.

Could the V in the circle be a Vienna proof mark?