Maybe worthwhile to check Paul Goff's website?
I have ordered a complete kit with him.
It consists of a pazon ignition + twin coil @ £132,76 and a magneto replacement housing @ £99.
Including a complete 12v conversion kit with battery, bulbs, ignition switch, voltage regulator +P&P (Europe) made a total of £359,25
The only thing I had to buy separately was the fixed pinion and nut to replace the automatic advance unit.
Will start the conversion somewhere next week I hope. Keep you informed