I would bet a £ to a penny that it is an electrical fault, common to both the driver’s door central locking and mirror adjustment. It might be a loose electrical connection or even a fuse supplying power to both. If you have the wiring diagram this should assist with possible faults.
It might be worth posting the question on a Golf forum – resulting in more comprehensive/knowledgeable replies.
A common problem (on all vehicles) is a wire break within the wiring loom due to the door flexing the wiring every time it is opened and closed.
First check all fuses to be OK, a broken wire or poor connection within the door cavity can be a nightmare, requiring removal of the internal door trim to access the components.
If you are not confident working on car electrics – take it to a garage for a quote to repair the problems.