Recall most advice given here in the past relates to ensuring a slight delay between switching on ignition and actually starting the engine. This gives time for ecu to sort itself out. Suggest a delay until fuel primimg sound stops, speedo has jiggled around (as it does if you watch closely) and settled to zero and immobiliser light gone out. Sounds a lot but only a few seconds in practice.
Agreed, mine has done this on 3 or 4 occasions and this always sorts it.
