Ok,, forgive me,, but I have sinned and grown old and need a bit of help sometimes. The No1Mk3 rear sights are ,,uhh,, rather hard to see at times...and since this was my trunk rifle,, carried everywhere I had a choice of firing blindly or making a change.
I removed the rear sight elevator and fashioned a scope base to fit the sight mount,,added a 30mm red dot and now have a nice clear fov and a much more old guy's old eye friendly sight.
Well.. my back is really screwed right now so a range trip is not viable, but a quick shot off hand at the steel spinner was answered by a satisfying ring and a twirl of the metal.