same problem on my 200 when i bought it. bloody child locks! :}
if you undo as many screws as possible from the doorcard and then pull it off. you will be able to reach inside the door to see whats going on.
in my case it was simple, the exterior door handle connecting rod had come away from the clip that holds it to the door lock. 30 seconds lsater i had clipped it back together and the outer handle worked again.
got the door open and turned off the child lock pronto
if you undo as many screws as possible from the doorcard and then pull it off. you will be able to reach inside the door to see whats going on.
in my case it was simple, the exterior door handle connecting rod had come away from the clip that holds it to the door lock. 30 seconds lsater i had clipped it back together and the outer handle worked again.
got the door open and turned off the child lock pronto