Madcratebuilder, I notice that your No5 Mk1 has a bayonet lug on the underside of the front sight. Mine does not nor does it bear any toolmarks that would indicate there had been one there in the first place.
There aren't many markings on it to begin with. It has a more recent etched in importation number (SER. MK4413***) and a number on the left side of the receiver below the safety reading DA24754. Is ther anywhere else I can look, there are several numbers stamped on the barrel, most of which are barely legible, with what looks like a cartouche of a crow which I assume is the marking of England.
I took it out to shoot yesterday but it was at the end of the day and clouds were rolling in. Only got two shots off and only one of them nicked the paper plate.
These sights take some getting used to... Anyway i really like the trigger on this thing compared to my Mosin and M1903. With a little tweaking this might wind up being my primary woods gun. That is if I feel like risking getting it banged up in the woods.