My BMW Xdrive Xline 25D auto returned a figure of over 60 mpg plus, on a 340 mile round trip last summer.
It was split into approx 300 miles M5 motorway and 40 miles of B roads, speed limits were obeyed at all times.
The auto setting was eco pro and my son was driving with cruise control set.
The local urban driving consumption figures average out at a fraction over 40 mpg.