This year I took part in an "eco" study for the University for which I work.
Averaged 27.9mpg over 9,000 miles between April and September this year. Which included three track days, visits to my friends across country and a driving holiday to Cornwall in Summer.
Considering I've owner the car for just under two years, done about 20,000 miles and never take it on short journeys (i.e. around town or less than 30mins drive) I don't think that's too bad!
It does help to have good tyres, nitro inflation, regular maintenance and the controversial "only shell v-power" fill ups.
So happy with the car's MPG. Really, really good GT car.