I've just replaced my W211 model E-class 220CDi with a September 2009 reg W212 model CDi, choosing the new model largely on the basis of the promised fuel efficiency. On mixed motoring - and I'm quite a fuel-conscious driver - I'm getting less than 35mpg, compared to the 40+ mpg I was getting from the previous model. The promised - and much lauded - consumption of 53.3 mpg is light-years away from my experience. Have I a case against the dealer, or against Mercedes themselves, for what seems such blatant distance between advertising and reality?