Discovery 4 locking problems

Hi recently purchased a Discovery 4. 2012 plate.

The front passenger side door doesn't unlock using the key, or the button on the drivers door.
You can get in keyless when stood next to it. But to get the door open (without being stood next to it with the key) , you have to pull the door lock button on the inside of the door.

Anyone any ideas what this could be? Potential solutions ect...

Thank you!

Door latch assy? I have had to do two doors on my D3 over the years, about 80 quid a door.
Well worth googling wiring splice and having a look see in the car