I average 35 on my usual stop-start mountain trip - this used to be low 20's in a 145QV. But if I ever get on a motorway cruise it's mid to high 40's.
(Came back from North Wales last week. Clear run all the way home. Averaged 49 with a full load). This is all off the trip computer though - not sure how accurate it is.
Mostly urban driving I'm getting 430 miles before I hit the yeller light. I've had 480 one time, but my alarm to fill up was going off every five minutes! It all depends how hard you drive aswell. Burning ppl off at lights tends to burn a bit of the ol' black stuff!