My brother just got one of these and I was wondering if anyone else knows anything about what they really achieve. The combined average fuel consumption is supposed to be 74.3 mpg (Imperial gallons, so around 60 mpg US). What he's actually getting is around 40 mpg (30/US gal). That's worse than the 2010 Passat tdi 170 I had which was getting 55 mpg (44/US gal) while I was thrashing it to see what it would do in 'normal' driving.

My brother has been driving carefully and the best he has seen is 42 average on a long run at speeds around 60mph. The dealership says they got 48 mpg which is within specifications.

So, 74.3 mpg is the figure on the window sticker and in all the adverts and reviews, but 48 was what the dealership got and they think that is OK.

The dealer tech said you couldn't expect good mileage until it was six months old. So does he really think it is going to improve 50-75% or more?

Any idea how to best handle this in the UK? Trading standards? Advertising standards? Or is this something Seat will be interested in dealing with, since the dealer is clearly smoking crack.