Tony,
Thanks for your response and the link to a previous query on the subject. Not sure this is of help to me though.
I was not aware that this was an old third brush type dynamo, I have seen a similar one in the wksp manual for a Canadian Mk1* carrier, but it had a box attached to the brush band and I assumed that was a third brush control box, and the one here was a later type.
The odd thing was that this was wired in to the vehicle prior to removing the engine, not sure if it was charging, and someone else removed the wiring, without checking the connections. It has just dawned on me, that this dynamo would be unlikely to be 12 volt, the WOT models were 12v, so must have been substituted in its later life. Looks like I am in need of a 12volt Lucas dynamo then
