Im not sure how people are getting such poor economy. I drive a 45 mile commute daily, mostly dual carriage ways and motorways, but about 5 miles A roads. I never get below 40mpg and typically average between 45-52mpg. I have recently been getting 48mpg on the commute due to the colder weather. Weekend town driving takes the tank average down to around 42-44mpg, buts thats expected what ever you drive.
I have spent the last few months ensuring the EGR valve is clean and working, the inlet swirl valve operates correctly, the inlet manifold is clean, the MAP sensor is clean, the MAF is clean, air filter clean, tyres pumped up correctly, boot empty hence the good economy.
A friend owns a VW Golf 1.9PD 130BHP, it always get above 50mpg on the same route. Which car would you rather drive though!