Thanks for the reply. The model is C4 Picasso, 2006, with the Navidrive Instrument Panel, Multifunction Screen DT. I thought the Central Locking button on the dashboard simply locked ALL doors when pressed and held in. That is not the case here, as when the kids try to open the tailgate, and fail, they open one of the rear passenger doors, then they can open the tailgate. I will check the menu/configurations buttons, and see if that is the problem. Cheers Rock