Marelli Magneto Tipo BL wanted for 250 Airone

Wanted for 1947 Guzzi Airone (Astorino) Marelli Tipo BL magneto. Were aslo fitted to PE250, Egretta etc and other. Rotation is anti-clockwise when viewed from sprocket end of magneto. There should be a direction arrow on there. The one I have is fairly worn and more worryingly the brass shaft is also bent. If I cant find one I may have to get this one refurbished and a new shaft made. Any recommendations on who would be able to do this for me? Tiggy