Based on personal experience, here's what I can tell you:

1) On the W202, the driver's side mirror assembly only consists of three saleable parts, the heated reflective mirror itself, the body color matched mirror cover, and then the really expensive internal motor/frame/mount system. Those are the only parts Mercedes will sell. The alternative is to find a used or recycled part(s).

2) To service the driver's mirror does not require going anywhere near the center console mirror adjuster. Why they cracked it, presumably by lifting it out, is beyond me.