I ended up installing it on the left side as per Autoinstruct.
While I agree that the camera is not exactly in the middle, it is now not in the way of the driver or the passenger and you can easily slide out the unit by pressing the button on the bracket and remove the power cable then remove the card if needed.
The cable gets closer to the headliner to hide and the fixing point of the bracket is behind the darkened windscreen, which makes it less prone to loosen in direct sunlight if it gets too hot.