No age of vehicle stated in your profile.
Does it have the earlier lock barrel or later handle without?
My central locking locks all doors but does not unlock any on the fob, and did nothing with the rear door (later version without key barrel).
I've retrofitted an earlier key barrel handle (thanks to cncfabs) and also cut the wiring to the rear door in the boot area and fitted a manual switch on the dash to control the rear door motor.