Why does the drivers door on my jaguar s type lock and then open again?

You will find one of your door locks is defective, with the doors all shut and you inside try to lock and open each door at a time and you will find one that is stiff or notchy to operate, that will be the defective one. You will probably find if you lock that one manually the central locking will lock the rest but don't leave it too long to replace the door lock/mechanism or you will end up with a door that will not open from inside or out like me. Anyone know how to get mine open ?