My wife is nagging me about the mpg of our 2009 Qashqai 2.0dci. I told Nissan we were disappointed compared with our 2001 Scenic 1.9dci, but got a non-committal response. The computer is indicating 36.7, as it has for the past few months, even though my wife did a 1,000 mile round trip to France recently, taking it very steadily. Or is there a special way to drive it to get the best mpg? Our Scenic is due to be taxed when we are away on holiday. Am I right in thinking we will have 2 week's grace to do this when we get back?