Tangent, but OK, you got me curious about the Enfield.
What is marked on the left side of the receiver? You called it a Carbine, and there really is only one (generally available in the US) original Enfield carbine, the No5 "Jungle Carbine
". It came with a flip up aperture sight, with a large aperture for ~200 yards, and a smaller micrometer type marked out to 800.
Does it look like this one?