I ve also had a similar issue on my other rear door but it has mostly resolved.
Rear door not locking vw golf.
If the lock slowly started to lose power speed locking and locking or would stop working intermittently and start again the motor actuator is most likely to blame.
Vcds was giving me 2 errors one regarding the lock motor failing to respond and another regarding the rear central locking not working which is related to the one door not working.
Vw golf 5 central locking module problem vw locking module not working 00931 locking module for central locking rear right f223 vw doors not working.
The manual unlock lever is located between the inner side of the door and the lock.
One door lock is not working.
I have a mk4 vw golf 2003.
When one door has the locking issue it is likely an issue within the door.
Be it the switch for that side latch or actuator.
How to remove vw golf mk5 door lock to repair central locking issue.
It can be accessed through a service hole with rubber grommet on the rear side of the door when it is open the red one is the manual unlock lever not my photo.
For further enquires contact wishart auto tech on 03 9329 8792 http wishartautotech.
I haven t seen any issues with it for a month or so.