Replacement Wing Mirror glass/mirror ?

[obelix54]

Abolutely gutted.

Reversed car out of garage and promptly smashed nearside wing mirror. The cover popped off and is unmarked.
However the glass & mirror element behind are smashed.

I rang the local BMW dealership who promptly quoted me £339 for a replacement ! so I did what most people do and looked for a replacement on google/ebay. Can anyone recommend a decent replacement ?

and also how to connect the heated element ? The BMW connector seems to have 4 wires going to the mirror but all replacements just mention two connectors.