I have been offered a 12 volt Beetle generator, and before accepting it I would like to know if it is the same physically as the 6 volt item, with respect to the Vince Leek mods to adapt it to the austin seven, also does anyone know its rated ampere output?. I also assume it would need regulation via a R B 106 or similar, due to it not having a third brush, it doesnt have a regulator attached

Unless you have found something different, the 12V version of the VW Dynamo cannot be adapted to replace the normal A7 (Type C35 etc) as the outer case is too large. If you have the 6V version, use the VW regulator which is normally fitted to the frame of the generator. The rating is 45amp. The only problem is that these generators normaly run at a higher speed when fitted to a VW the result is there is often no output below 30/35 mph when fitted to a Seven. However they do vary and some seem far more efficient than others. The positioning of the brushes in relation to the field coils is critical if you are contemplationg this conversion..