Re: I have a...
"... 3-litre diesel engined car from a well know German manufacturer which has returned an average fuel consumption of 38.4 MPG measured over the past 2 years. A friend has one of these twin-air Fiat things and has averaged 26 MPG over the past 8 months. We both drive a mix of shopping/school runs/motorway journeys.
...cannot compute... :-)"
Change driving style. Brake-happy driving is expensive.
My 7 year old old-tech petrol easily does better than 42MPG on the commutes, 49MPG on a long run.