Dear Colin.
Sorry to hear about your BX Colin,

Did they just smash the
window

or did they damage the paintwork aswell
It might be worth putting some warning stickers on the front
windows and fitting a flashing led warning lamp where it can be easily
seen

Or fitting an immobiliser, they usually work.
I fitted an immobilser to my SAAB when I first got it 13 years ago,
and nobody has even tried to pinch it

despite it being high on a scrap
mans list, because they weigh so much
I shall be fitting one to the BX TXi when I find the right model of
immobiliser
I hope this helps Colin.
Vince