I would suggest that you should contact VW again and ask them why your digital screen is showing the speed in kilometres and not miles per hour. It might have something to do with your onboard computer and fuel sensor playing up.
Both my previous Golf and the current Sharan have that. Iirc from when I looked into it, it was because both mph & kmh are required to be visible, on old analogue dials they had dual markings but on the new digital dials they display the selected unit only and so the other unit is displayed in the centre bit.