Thanks for your help.
I can see the material is approach should work. In split screen with 2 or more players all looking at the same character, the name ‘tag’ appears for each player as you would expect.
The difficulty I am having is have the actual widget context shown. One I apply the material to the widget, I get the camera behaviour I want, but the appearence of the widget, is purely that of the material, i.e the colour.