Mine does this regularly, i have found that a light tap on the drivers door, or even shutting the door will trigger the central locking.
Mine is an old '96 model, with single point central locking (No fob, the drivers door lock isnt motorized)
May be something to do with the contacts on the door lock mechanism themselves
Well my Td does the same too. Some times the Mav is in the garage, and I hear a click and all the doors except the driver's door locks.
Sometimes does it when I close a door.
I fitted a central locking system 18 years ago, as part of my alarm, and a locking solenoid for the driver's door. The driver's solenoid doesn't activate, so I know it is not my system or my wiring.
I know the answer lies in the Driver's door lock mechanism, but since it only happens twice a month, then it is not on the list of priorities, unless it starts to unlock the doors....
Next time the door panel comes off, I will have a look and sort it.
Bad connection, or water maybe... What ever the problem, it is a common fault.
Can be irritating, but what concerns me, is if it is doing it regularly, ie trying to lock a previously locked set of doors, then there is a risk of eventually flattening the battery..
Just a thought... Would take quite a while though...
Rustic