For a while, when I was commuting to & from LHR, I tried the V-power diesel. The increased cost was not cancelled out by better mpg, which worked out the same. Granted, the engine ran smoother, and I used it when away with the caravan so it would hopefully pull better. I seemed to not need to change down as much on long hills while pulling my 1100kg of large white box. However, I will be interested to see what happens with my latest auto version of the trusty 150-horsed 'wagon...