This has been an interesting post. I can see the rifle is in fabulous condition; but how can you be sure that it is unfired apart from proofing? Unless you've personally picked it up from the proof house and stuck it in the safe.
I have a Maltby that was stored for over 70 year's; it was a parachute drop to the local Frenchicon Resistance in the summer of 1944. It came with a bandolier of the original ammo and the original bayonet and oil bottle.
When I got it; there were no wear marks on the magazine plate or the bolt rail edge. But I know for a fact it has been fired; not enough to show any real wear and tear; but fired all the same.
It cost 750 Euro's.