hello steven, i tell you what i can see,
lee enfield no1 mk3* made in 1917
the markings- 303 british and 9ka are not factory or military markings.
d26 looks like a military marking probably a rack number. the broad arrow above is a government ownership mark.
the factory it was made is not stamped in the usual place....is it marked on top of the action near the bolt SSA or NRF?
the wood beside the rear sight has been removed or broken
the lee enfield is a beautiful rifle i have 7 of them
The makers mark is SSA and is on the leftside of the bolt.
Also the #'s are a match on the bolt, nosecap and barrel.
The wardepartment arrow is also marked on the sling buckles and there is a III marked on the safety.
Gonna get the bayonet for it this weekend with a box of deac .303's and one clip, all from the great war.
The brass disc is for unit markings-nothing to do with preventing cracks in the butt wood-post 1920 made rifles don't have them as markings were then stamped directly onto the wood-the best book on the subject is 'The Lee Enfield' by Ian Skennerton if you're interested in the type.