The round trip to Brooklands today was about 120 miles and the average from the trip was 69.7 mpg and included a journey through Westminster, Putney and the City and half the M25.... Amazing.
My current Demo is a 1.3 GP it's getting 54.5 mpg engine is still very tight only has a little over 200 miles on it. SO if you can't beat that your not trying.