I am a driving instructor and I do about 700 to 800 miles per week. My question is, would a diesel car be better for me? At first glance at my weekly mileage the answer would seem obvious, but here are the factors I have to consider. I drive a Ford Focus Zetec 1.6 petrol at the moment and the diesel would be the same model. My franchisor is saying that, although they charge a £25 per week supplement for the diesel version, I would still be saving money even after absorbing the supplement. They get their information from the official figures released by Ford for their combined driving situations. They say that anybody doing over 500 miles a week would save money. My problem is that my mileage is nothing like their simulation of real driving.

When learners drive my car its nothing like when I drive it. I also do a lot of reverse manoeuvre lessons where for a 2-hour lesson the car is running the whole time but we don't go more that 15 miles or so in total. My current car tells me I am averaging 12 MPH and 30 MPG. In your opinion do you think its worth me getting the diesel Focus?