I am having some difficulty finding hot and cold handles for my shower unit.
The diverter says ELJER on it and seems to be something called a US Brass
Valley Line with an Old Style (spline)

I tried a Fit-all one from Danco which seem to be useless as it both seems
too long to fit on the spline, it's fit-all attachment which tightens with
three small allen-key screws strips the spline and doesn't stay on and the
plastic seems to have started to crumble BEFORE I even started to use it
(back to Home Depot for that one)

All I have found at any hardware store seem to have an early fifties retro
look about them which I find personally offensive

Does anyone know a FitAll manufacturer which makes a proper line of vaguely
modern offerings or where I can get one specifically made for the US Brass
Valley Line please?