My C-Max Is So Thirsty

I have a 2006 C-Max 1600 TDCi Automatic which I've recently acquired. After owning a Renault Scenic 1600 petrol engined automatic I was expecting a good miles per gallon return from the C-Max in comparison to the Renault. However, in spite of driving in a sedate manner (not burning rubber when pulling away, not doing kick-down changes and using the Dura-shift to get into 7th gear at 50 mph) I can't get more than 37.3 mpg. Are there any owners with the same model car that can comment as to whether that's all I can expect?? My local Ford dealer has carried out a major service once I bought the car, my brakes are not binding and the tyre pressures are correct. Any feedback would be welcome.