2.0 tdi b6 sport bkp economy?

[seb.g]

Hi, my dad has got a 2008 140 tdi b6 sport estate. My qyestion is what sort of mpg figures can be achieved with these? i ask as looking at his average, it is only saying around 40mpg, and he doesnt exactly drive fast. The car is fully serviced and runs very well. Thanks