I found it!
Ok, looked at a few things, ordered a new set of plugs, good job too as they were not in a good shape, it looks like the electrode has burnt away, possibly indicating a timing problem.
Also the diagnostics indicated an issue with the crank position sensor, as it was easy, I took it off, and measured the resistance, which at 140ohms indicated it was not good.
When I pulled the leads off the coil, 4 of them were full of white corrosion, and black carbon from arcing.
So a new set of plugs, a new set of leads, some cleaning up of the coil terminals, and a new CPS, and she now fires up great, idles and runs smoothly, next test will be to launch her and see how she handles at speed, and with some revs!