Hi I had the same problem with mine and I read all the posts on this forum and the are all wrong.
If you sit in the drivers seat and press the door unlock/ lock button and you here a click from where the bonnet catch is then here is the problem.
The fuse box located under the drivers footwell at the right hand side is receiving the signal but is not able to switch the relay for the other doors.
I think this is a temperature problem as when it is cold it works fine.
Change this fuse box , it is a bit fiddly and will take an hour or so but should cure the problem.
BEWARE IF YOU GET A PRE 2010 FUSEBOX THE FOLDING MIRRORS WILL NOT WORK AFTER THE FUSEBOX IS CHANGED.
HOPE THIS HELPS
