T reg ford mondeo - locking system/central locking - spartak

Hi I have a T reg ford mondeo. I replaced the battery in the key for the central locking, the central locking did not work properly occasionaly it would lock then not, now I have to lock the drivers side door first the lock all other doors by the passenger side. Can anyone give me some advice on what is going on please.

T reg ford mondeo - locking system/central locking - elekie&a/c doctor

I would think that the drivers door locking actuator is faulty.