Can't lock my door on the passenger side...

Didn't know if this was the design or not but can't lock or unlock on the passengers side. I have to go to the boot to lock the car. Any ideas why? Or whether you're supposed to?
thanks
 
You should be able to use either side (or the boot) to lock/unlock the car. I regularly use the passenger side door to do this.
 
Well the drivers one is a common fault to stop working, guess its just the same on the passenger side.. My drivers side occasionally doesnt work...