well i was told by a mate he uses nothing but shell fuel in is motor as he as tried and tested morrisons/tesco and shell,and gets more to the gallon on shell.so when we went up to scotland in october i tried this out,we filled the tank on my hilux with shell diesel (not v power) and we got from the garage in stoke on trent to tesco in inverness (402 miles) on the one tank,we filled up again there as the fuel light was on.on the way home we topped up again at the same tesco.so now we should get back to stoke on trent to top up again,wrong we were in lancashire on the m6 and the light was on.so we were around 70 miles short to the tesco crap.so now its very rare i use anything but shell,and most of the shell stations round here are around the same price as the supermarkets.