just filled my 300tdi Disco up, 12 gallons to do 412miles just over 34mpg, I know my speedo is correct as I got a traffic cop mate to follow me to see how far out mine was/is but it is spot on with 235/70x16 BFG AT. That mileage included a days green laning with Yella and Dave in N Wales, towing a trailer with a weight of 2.75 tons for a 60 mile round trip and my general commute to work. I do not drive like an old granny (contrary to what yella might say) but keep the revs below 2500 in each gear just driving with the torque of the engine.