My '51 S6 4.2 has just given some grief in as much as the offside rear door will not unlock or open! The locking button moves up a little then goes back to bed when I unlock the car and refuses to go right up and stay up. Even grabbing the button and lifting it fully has no effect. Therefore, I can't open the door to get the door card off and investigate the problem. Neither outside nor inside handles let me open the door. How do I get into the gubbins ???? Any help please . . . . .