As you brought the subject up Johnie J I'll add a little to it
Started to reconnect the wiring on my Flash (6 volt + earth) far too many wires in those pattern looms and the wrong colours, I trimmed out those that just loop the loop a the battery end and made it more like the A10 wiring diagram, given the price of the cheaper ones ( the dearer ones are probably better quality and correct) I would recommend any one to make up there own loom, but this is not my question.
I have a Vreg which is negative earth (6volt or 12volt by cutting a wire), the Flash is Positive Earth, is there anyway to convert this to positive earth, I'm thinking maybe take the Earth wire to the Ammeter and the Ammeter wire to earth.
Looking forward to your chucles, I don't want to damage it,as if it not possible I'll sell it on