Mercruiser Thunderbolt Ignition, no spark

Is anyone familiar with the thunderbolt ignition, although I figure it is not unlike any other electronic ignition on these boats.

A bit of background I started the thread "Electrical Problems on '83 Nautique'

Summarized the boat ran fine, then seemed to develop an electrical fault, wouldn't start (as in starter would not turn) bridged out solenoid to get back to the shore. Then it started again okay, but under hard accel it started to surge, which I would say was a sudden shut off then back on again feeling, it wasn't spluttering really just off and immediately on again pulling hard, no delay.

So now boat is home, I started tinkering, after reading up about these issues a little more, I wanted to check my "points etc" at that time I hadn't actually bothered checking these things but clearly on inspection noticed it has the thunderbolt electronic ignition, (I pulled the disto cap only)

I closed it back up (didn't even pull the plug wires off) all back in exactly as I pulled it off.
Measured the coil (I think I did it right) and tried to start her up again, turns over fine, bar a dodgy Bendix but no start, not even an attempt at firing,
I sprayed a bit of quick start to see if it was a fuel issue, but nothing, I pulled a plug and grounded it, turned it over and nothing, not even a feint hint of a spark.

Where do I start we have just gotten into our season here,