Wing mirror casting
 

Hi Forum,
Just had some vandals break my retractable wing mirror (W140 body type).
This is the third one of these I have had broken although (ahem) I did break one of them myself on a traffic bollard.
They always break in the same place.
There is a metal casting approx. D-shape which holds one of the pivot pins for the wing mirror assembly.
It's Mesac zinc alloy so very difficult to weld or repair.
Now this is a $10 casting but Mercedes don't supply just that part, so I have to either pay $650 to MB for a full brand new wing mirror assembly or I can get one from the breakers for around $250. Either way, I end up buying the complete motorised unit with the mirror and the outer plastic housing.
And it is probably a design feature that it is always this part which breaks so that the more expensive parts don't break.
However, what is the point of that if they don't sell this replacement part on its own?
Does anyone know of any enterprising company which has had some of these castings made for sale?
It's the driver's side (UK, so that's the RHS of the car) one which I need on this occasion.
If not, I might do it myself and get some spares made for the rest of you, but I would appreciate any knowledge you can give me.

Regards