Hi, update; the car actually reproduced the fault this morning pretty much as the customer described.
Later, I was able to probe with pins the CAN wire terminals in the engine ECU multiplug and capture some activity, on replaying it frame by frame I found these 2 that I have posted below. Unplugging the ESP/ABS control unit after this did not stop similar 'wavy' traces appearing so I presume then that the ESP/ABS control unit is not the cause of the problem.
I would be grateful for any comments on these traces please.



Thanks, Martin.