I get 31mpg tank average on my 150bhp AUM, mostly a 6 mile to work and back commute.
If I have a few long journeys in there, then 35 over a tank, 40-42 on a journey according to the computer possible. Best i've seen from the computer is 47 from a 2 hour journey.
If i'm ragging it, 22-25.
When my thermostat went though, I was getting about 24-25 tank average. As soon as I fixed it, back up to 30/31.
edit - for clarification, that's all calculated by filling and recording with FuelLog, the actual trip computer seems to be about 2mpg too optimistic.