Superb find and from a sleeper that never want through the VII mods, the next challenge, find a suitable No1 Mk1 action and bolt, or a worn out wall hanger with some fight left in it and start a re-build!
"lost" its action back in the 1950's/1960's more than likely, when it was just another cheap old warhorse waiting to be sporterised, probably had a Lithgowheavy barrel fitted and it's woodwork cut about..
At least someone had the presence of mind to preserve it and squirrel it away.