As the title says really, I had a typical white van driver take out my drivers side wing mirror and then drive off. I have the police involved and insurance company. But just wanted to know the cost of one of these units.

Couple of hundred IIRC, but you might find one at a breakers.

I don't know if it is the case, but they look mighty similar to the polo ones.

How much is broken, if its still attached to the car chances are you just need a new top shell and indicator which aint that bad. I whacked my passenger one against a wall quiet hard earlier this year and it was cheap to fix because the glass and the mirror mechanism remained intact.

the cost of one of these units.

Same happened to me cost, approx three years ago, was £280.00

Have fun trying to get it back, I just took a deep breath and paid up.