Door (dead)lock failure.
The passenger door lock does not engage when activating the central locking. The door opens and closes OK with either interior or exterior door handle but the mechanical lock does not operate. I believe the problem was caused when the door was being opened simultaneously as the central locking was activated from the key fob.
I would like to narrow down the problem and establish if the repair is a reasonably easy fix or not.
My suspicion is that it is a mechanical issue as the central locking system works normally otherwise; other locks are activated, the door pin rises and falls normally and the LED blinks normally. However when the passenger door is opened the alarm system is deactivated.