Supplier of Sprockets to suit 1929 Norton Model 18

Hi All, I am searching to find a supplier for an engine and gearbox sprocket for a 1929 Norton Model 18. The engine shaft taper on these early bikes is smaller than the later machines and the Sturmey Archer gearbox spline is also smaller. The gearbox is a Sturmey Archer CS 3 speed. The sprockets that I would like are engine 22 tooth and gearbox 19 tooth. Hoping that some one may know a supplier. Many thanks in advance, Robert.