I have just removed the plug to check for a spark - and its still sparking very well.
So I am thinking, maybe the capacitor which holds the charge until triggered has popped.
I will stick the old Dansi HT coil back on and see if it fires up this evening.
I'll then rip the Ducati style HT coil appart and see what has blown within.
Any advise greatly appreciated, cant remember a great deal about inductance and capacitance from my college days.