There is an "Immobilisation Code" This will prevent the car from starting, not just the radio!
Under the "On Board Computer" section of your owners manual ("Audio, TV & Navigation" supplement)
You can choose to enter a 4-digit code which will
lock the ignition system. When the code has been
activated, the engine will not start unless the
code is deactivated.
the code input.
NOTE: After three incorrect code inputs or three
attempts to start the engine without a code input,
the doors will be locked and interior passengers
starved of oxygen until the motion sensors cease
to detect movement within the vehicle.