Back on topic...I've logged my fuel useage (not with the DIS, calculated using an app on my iPhone) since I bought the car last year. I have done 26,359 miles so far and averaged 31.79mpg on Shell V-Power (Nitro+ more recently which gets me and extra 30-40 miles per tank compared to the original V-Power!). I do 300 miles on the motorway every week during the weekdays and 140 miles around town every week. I fill up every single week of the year (except when I am on holiday) and get 440.6 miles per full tank on average. All this works out at 21.2p/mile (based on average price of fuel @ £1.479/L).