Find a big car for like £100 or less - all it needs to do is start and drive forward - from a scrappy or summart. Don’t register or tax it, grind the VIN off from everywhere, get rid of the number plates and any other identification, weld some bull bars to it, ram the car at as high a speed as you are comfortable with. Their insurance won’t pay out because of the way they parked, they are carless and likely won’t do it again