So, Emerald replied and sent me a new map file with extra ign corrections at 20 degC (same as Dan suggested) and blimey, that worked amazingly - car started on first turn of the key
Attached is datalogger trace with more sensible parameters recorded - and I cannot see anything wrong with the engine speed (purple line) although I only went on a short drive and there was only a slight hint of misfire.
newMap.lg1 newMap.lg2