Thanks for all the replies.
Just to eliminate a few things; fuel was new and so was the oil(?). Battery was also new but spent a month or so fixing it. I am sure I charged it before we went on the run as I did with all 3 batteries for all 3 bikes but the seed of doubt is sown there...
I am pretty sure all electrical connectors are fine and carbies also ok.

No one has mentioned if there is an electronic bench test you can do to both the CDI units and the PGM.