I went for a factory visit yesterday, a distance of 80 miles mostly motorway. It was a great visit but my speedo acted up there and back. After motoring for about an hour the speedo started slowing down to such an extent that when I was travelling at 65mph the speedo actually read 30mph! This happened there and back from the factory. The mileometer recorded the correct mileage. This is on a 2014 4/4. Has anybody else come across this before?