I travel through a 50mph roadworks which show 50mph on my Ceed and 55mph on a Golf when compared to the readings on Tomtom. I always stick to the satellite speed of 50mph. I would assume the Ceed is giving a more accurate result? Secondly, how does this affect stated mpg of such vehicles if the Golf is measuring different miles to a Ceed? Is it down to wheel size? Would like some views on this topic.