O.K I picked up a 12v 0.60MA LED from maplins today and tested the 3 pin plug whilst cranking the engine. The LED flashed on and off from both outer negative pins when tested in turn. I could just about see the LED flashing on / off quickly but as soon as cash allows i'll be buying a noid set to keep in the toolbox

So it looks like the PCM and the coil driver are good, any ideas as to what I could try next?