You need to take a look at the Winchester pump action .22... It may well have been a service rifle! During ww2 the dept of defence called in a lot of rifles from private ownership to be utilised for training and even the defence of the country in the hands of home guard units... IIRC (and as usuall, I stand to be corrected here...) Winchester Mod 1896 (or something) pump .22 rifles were on the list... I have seen it written somewhere... just cannot recal where... Someone with more knowledge o the right book reference might be able to say if they were marked by the D^D.

As for a .303 "from the war".. I don't think so... but there were a lot of periods when demobbing servicemen were given the option of buying a new rifle dirt cheap as they went out the door so to speak.... Once again, someone else here will have more info on this too.