Anti slim jim plates for the doors (will fit both front & rears):
191 837 273 - rip plate - left - £3.07
191 837 274 - rip plate - right - £3.07
Basically what you do is unbolt the door lock block, and it slips into the hole. They only go in one way, which becomes obvious when you do it as there are 2 holes in it that the bolts pass through
As you know, quoted prices don't include VAT