I bought a Rio Chill 58 plate in January and it's now showing about 16500 miles. I can't seem to average more than about 30mpg. I do mainly short runs around town but interspersed with longer runs most weeks, I try not to be lead footed. The car is under warranty until September this year and has been back to the dealer's twice, they apparently carried out diagnostic inspections but found no fault records. The last dealer updated the ECU but there seems to be no difference. Am I expecting too much, are all these models heavy on fuel or is there any tuning that can improve things.