As my car is still in Warranty I have since had it with the dealers - they had it for two days and their eventual solution was to fit a brand new mirror…
From what I can see they have also filled any gaps inside the mirror mounting with black sealant. It’s not whisper quiet but a lot better on the motorway. I got the impression that it’s a case of adjusting the mirror to its mount as there is a certain amount of ‘play’. The new mirror looks identical but something has changed to make it a lot more bearable.
Good luck resolving it...
From what I can see they have also filled any gaps inside the mirror mounting with black sealant. It’s not whisper quiet but a lot better on the motorway. I got the impression that it’s a case of adjusting the mirror to its mount as there is a certain amount of ‘play’. The new mirror looks identical but something has changed to make it a lot more bearable.
Good luck resolving it...
