Starting to have some real issues with our 62 plate Countryman One D.

The passenger door is now failing to open regularly without having to operate the inner door pull several times.
I can hear the latch operating at the door lock however the door doesn't open. After several attempts at operating the inner handle she will operate and open.
The symptoms do not repeat themselves once it operates. However when left for a few hours it occurs again.
Any ideas? I have had the door card off and all seems well with the cables etc.