How old webley mk3 supertarget?

The Mk3 supertarget was made between 1946 and 1975. If it has Parker Hale sights and a nicely shaped and checkered loading tap lever its an early one. If it has a plain loading tap lever and PH sights its in the middle and the later ones had Anschutz sights, and no brass box on the pistol grip to hold PH inserts. It is difficult to be more precise from serial numbers as there is not the logical sequence found on some other makes.