That's a pretty impressive amount, probably about the highest I have seen. I just completed a short 2.5hr each way trip through the Benelux countries which included getting lost, some traffic and bad weather conditions. The average was about 45-50MPG, with on the way there being at the higher end of the scale - with little eco driving unless I was on the speed limit and traffic was flowing relatively normally. I get the impression the car may be tuned for UK roads (no surprise as it is the best seller across the channel) as if I sit on the equivalent of the UK speed limit ( which is lower than the speeds here) then I get very good fuel efficiency but the minute I go up to the Luxembourg or Belgian limits I notice a drop in efficiency. Anyway if I can squeeze 50MPG out of it I'll be pleased but even more would make me happy
Rod, tuning has nothing to do with the effect of speed on mpg. It's a simple case of physics ie the faster you drive the greater the atmospheric drag. The effect is so dramatic that, say you double your speed the drag increases four fold, heavily reducing mpg.