Hi, I've removed the vehicle battery to charge it up but can't see a way of locking the passenger door. Central locking on key fob not working without battery connected. Drivers door locks with key and habitation door locks from inside. Am I missing something obvious with passenger door? There's no lock on outside and can't see a 'button' to press to lock from inside. Fiat Ducato X250, 2011 Bessacarr. Thanks, Paul