Wife is waiting for her new to her superb to be delivered.   When the garage were valeting the car they noticed that the drivers door would not unlock.  They could open it from the inside.  They fitted new batteries in the key and it worked, they tested the car all day it worked fine.  Next morning same fault again it would not unlock with the key...  any ideas?   It's a 2018 technology manual 2.0 tdi.

Since no one else has answered, here is my experience -

 

I have had the same sort of  fault, although the problem was the driver's door would not LOCK from the key, although the other 3 would.

The other symptom was that the automatic locking at 10 mph did not work. It tried and failed each time i went from a standstill.

 

I have no real idea why, but the problem went away when I gave the car battery an overnight charge.

An ex-mechanic friend suggested there may be some corrosion in the lock switch connectors in the door which offers additional electrical resistance and means the a low battery doesn't have the oomph to overcome it.

 

It's happened twice in 2 years of ownership.