Success, put "delay (15);" between shutter high and low in the lightning trigger part of the program. Did some testing and 15 millisecs was as short as I will go, 10 didn't work for me. It will only run once like the sound trigger then reboot to make it go again.
Borrowed a dyno from work and labelled everything, made a housing for my mic from a cut down dry wipe marker body
I am finally going to fit the lid, test it in anger at wkend.
Will post some pics on Flickr if it works ok.
Simon