I have just double checked my mpg readings and my mapped 130bhp tdi has just got an appalling 31 odd mpg i only got 450 miles to a full tank.

This was mostly town driving and am i right to assume the diesel's suffer more in the winter due to the heavy oil?

I know i run 19's as well which don't help but could there be something wrong with my car, i've replaced the maf sensor about 10k ago