Update: The passenger door must be fixed in the same manner. It hampers operation of the now working drivers door. If the car is unlocked on the passenger side during cold weather, the problem of delayed unlocking is back. It is then impossible to operate central locking from drivers door until the weather turns warmer again.
The microswitch on the passenger side is soaked in the same type of stiff grease, and hence both sides must be fixed for trouble free operation.
I will be an expert on disassembling Focus doors after this !