Ok ok,I know this has been done to death and at the risk of causing everyone to loose the will to live I'm still going to ask as I've spent almost a day reading threads with no success.

Everything on the central locking/windows/mirrors/interior lights/door led etc using internal armrest switch or fob or key in drivers door lock or tailgate lock works as it should except the following:- using the key in the drivers door lock to lock the car, only the mechanical part of the drivers door works (no other doors lock or the tailgate, no windows close, no led etc)

Its as if only that bit of the electrical system from the drivers door lock, when locking the car, is missing. Maybe coincidence but this only happened after I replaced the moisture barrier in the rear drivers side door as it was letting water into the car.

Any known faults or ideas?

Car is a September 1999 Octavia SLX TDI 110 Estate with 44,500 mls on clock and owned from new and mostly garaged.

Sounds like a door barrel fault, is the linkage on both ends correctly?.

Drivers door has never been appart/opened up. AFAIK All workings of door mech are fine and work as should by all other methods unless you try to lock car by using key in drivers door lock. So, I presume that all linkages are OK otherwise would there not be a problem when locking by other methods. Thanks for your suggestion. I was thinking along the lines of possible micro switch problems. Must say I'm disapointed if this is the cause consdering the low usage.

I think you can buy a barrel repair kit from the main agent which is fairly reasonable which may contain what you need - think there is a linkage part on the barrel that breaks.

Thanks for the suggestions. Looks like I will be exploring the internals of the drivers door.

I think the mechanism you turn with the key is simply turning a microswitch to activate the central locking.

Maybe this switch is busted.