The last Norton contract, S5161 would appear from photos to have the ball-ended Amal type top controls..I believe they had 7/8" bars.
There are two types of Norton Doherty controls which have interchangeable internals, the pre-war squared-off style with a large hex screw and a later more rounded type with a small-hex. Both types are of all brass construction except for the top cover which was plated steel, they were originally dull chrome plated and later cadmium. They are quite a clever design as there is an internal tension nut and 'D' washer. Unlike with Amal and the crude Bowden set-up, the top cover is purely a dust cover and its loss does not result in a loss of tension on the lever..not that they come undone, as there is no rotating motion.
I have seen the later type cadmium-plated in 7/8" too, which suggests that some 7/8" bars WD16H may have had them (or were they simply supplied as a spare part ?)
In this photo, above are the early pattern and underneath the later-war type.
This is the late Doherty with the cover off. Lock washer etc. are identical to Pre- / early-war.