I managed to get it started again, it idled for about 3 mins then died when I tried to drive it off. Couldn't start it from there.
I thought it was the dizzy module so replaced that with a new one I had ready for this situation. Still no go.
Did numerous checks and it all pointed to the coil. Got a new one. Still no go. Things were pointing back at the module. Replaced the module with a second hand one of unknown condition I had kicking around. BINGO - EA81 was a goer once again!
So in summary:
If your EA81 dies suddenly, check both the coil and the module - if you are suspicious of the coil run a known good one before replacing the module!
Hopefully this thread will save others a few bucks - as I've killed a $75 module that was straight out of the box

Cheers
Bennie