Parts for the magneto are obtainable from a number of suppliers eg Villiersparts or magneto-ignition (took over from Independent Ignition) these are just a couple there are others.
The WICO part numbers are 06401 contact set, 06400 condenser set and X2089 breaker box cover unit. The WICO A576BZ was standard equipment on JAP 4/2, 5 & 6.