Thanks for the quick reply - and excellent photo re the tailgate.

Are you sure about the auto-locking? If it is meant to work like that, it is different from the Passat - have just tried Passat (TDI estate 2001) and find:

1) If I unlock it with key-remote and do nothing it auto-locks after about 30s.
2) If I unlock with key-remote and get in, without inserting key it doesn't auto-lock.
3) If I unlock with key-remote and just open and shut either drivers door or the rear right door that also seems to cancel auto-lock.

If there is not a fault then that is good news - am a bit trigger happy about faults at the moment.