Well as nobody had a multimeter handy I just got a car battery and picked a wire at random, hey, its 50-50 innit

It worked!

But my curiosity got the better of me so I swapped the wires around

It still worked!

BUT the noises the sparkplug makes are different depending on which wire goes to pos, and which to neg

One way its a high pitched "eeeeeeeeeeeeeeee" noise, other way it sounds like bad TV radio interferance/static. Spark looks thinner but more constant and stronger on the "eeeeeeeeeeeee", and the sparks much wider but almost see-thru on the interferance/static noise way.

Which way is right? Im guessing "eeeeeeeeeeeeeeeeeee" as im sure its what it used to do on the Cossie