2008 1.6 TDCI with the dreaded DPF here. Does short runs most of the week, the odd long run at the weekends. No problems to report after 50 odd thousand miles. Dee is spot on above - this time of year, 450 miles out of a full tank on short trips, closer to 600 on mixed.
Tax is £30 a year. Love this car. Other than glow plugs going, not a single problem. And yes, it is starting to develop the odd rattle, but it's a 6 year old car!