[Neil]

The recommendation is to lock your car when you go to pay anyway. It stops people trying to nick anything in the car while you are paying which does happen. No excuse with remote locked etc. I always lock mine when going to pay, especially important if you have kids in the car. I have my cars car jacking options switched on as well so it locks itself when you set off, one button press unlocks the drivers door and 2 presses unlock all the doors.

Central locking is often blamed for car jacking because all you doors could be unlocked instead of just the drivers in the pre central locking days.

My car is a Mondeo by the way and you can turn the car jacking option on and off if you know how too. Probably the same method on a Focus. If anyone wants to know how just ask.