With the 1.9 JTDM 16V Qtronic (auto), I am averaging 38 mpg overall for 1500 miles per month. That's a daily rural commute of 15 miles each way, and a few hundred miles at a weekend to umpire a hockey match or two. The computer is within a few % of the brim-to-brim calculation.
Leaving home and getting on the motorway, the trip mpg climbs to about 45 mpg after 30 miles or so, then gets even better over the 20 miles of 50 mph on the M3. By the time I get to Sunbury it often betters 50 mpg. But, as Stan Laurel says, it drops back towards 40 mpg once we get into roundabouts and traffic lights.
I haven't been recently, but I used to have a regular trip via Milton Keynes, where all those roundabouts are absolute death to fuel economy. If it shows 45 mpg entering the first roundabout, it'll be 35 mpg leaving the last: let's say 20 mpg for the 10 miles across town.
Last edited by ChrisH77; 03-03-16 at 21:35.