Best advice would be to get someone else to drive it slowly around in an empty car park with you standing close to each corner of the car. That way you can narrow it down to one area. My only thought was could it be the automatic (electronic) brake releasing? Some other EVs can make a 'graunching' noise when first setting off or 'creeping' along slowly and you only hear it because the car is so quiet otherwise? Just a thought.
What sort of speed were you doing in the audio clip? Admittedly doesn't sound like the brake, more like a suspension arm bush (or something like that, I'm no Mercedes technician!)
What sort of speed were you doing in the audio clip? Admittedly doesn't sound like the brake, more like a suspension arm bush (or something like that, I'm no Mercedes technician!)