We have a policy at our work (that was recently changed actually)for vans or cars (the install guys have vans). The only responsibility we have if you own a company car (as opposed to what I do and take a car allowance and buy my own, I have more responsibility like maintenance, tax, insurance etc) is that you need to keep it looking clean and presentable inside and out. Things like dents and scratch gets VERY frowned upon by our MD but there isnt anything he can do (Im sure if he could he would) and most times if they are small, they are just left and will be charged to the company when the cars go back to lease company.
Don't quote me on this, but I don't think you can make the employee pay to repair a scratch, dent etc if its insured under the company.