No ones mentioned the MOTTY stamped onto it. As a target rifle fan, that stamp instantly made this a very collectible rifle for me, Motty made sites and a few rifles, ie not many, and out of the many range rifles ever made, few have identities that can be tracked to their maker. If its original internally the bedding is probably well made, except for now needing the usual, (usually annual) refresh due to age and settling.
You've found a unique and collectible rifle, I'm green, and it wouldn't be my plinker lol, it'd be a sunny sunday rifle only, well done on a great find. You can www search for motty sights and rifles, there's not much as its a small group but some info is around. I think there's some motty sight pics on enfield resource.com