had chat today with garage, think they haven't been able to book the electrician in yet, anyway, today it failed to start which is what we want so the sparky can check it out while the fault is there, car is outside in garage compound. Seems the PCM is that large metal box low down between cais/battery/water bottle area, they need to be cool hence on outside of car and also subject to weather there too. In order to access these they have to be split in two halves and this where weather could access the pcm and cause problems if not sealed back well or from factory, so it's an outside possibility of ingress causing software/hardware fail.
Yes Dave it is possible for Mountune to see if there is a software/mapping fault and they could tell also if it is an actual hardware/board failure, not sure if the electrician can tell this, so if software it is possibly fixable. Electrician is booked for tuesday.