[Graham]

I have a number of MG Vanquish Can Am cars missing mirrors, the majority of which seem to use the same piece. 

Can anyone suggest a source of replacements please? I'm not expecting 'unobtanium' originals but some suitable cheap, repeatable and easily obtained parts to give them a finished look.

Thanks.

The problem could be that the Vanquish models are somewhat over scale, so maybe “ scale” after market substitutes may not look quite right. 
But do you have a photo of the actual Vanquish mirror which was lost ?