One option may be to set the rear door lock to unlock then try the central locking. Open the rear door and above where the lock fitting is you will find a small black thingy the can be turns with a screwdriver or the key that manually opens the passenger door. Set this to 'unlock' and do the same with the other rear door then close the doors and see if the central locking function has righted itself.
Ray, June 2019
