I've seen over 41 mpg but in very 'specialised' conditions i.e the engine was still warmish from when it was last run but enough time had elapsed that the trip computer was reset, then it was straighnt onto a rural A road at a steady 45-50 mph for an hour or so without any harsh acceleration or braking. It was mostly downhill too come to think of it...There was a convoy of cars ahead of me and no opportunity to overtake all of them so I just took it easy.
Do-able but not everyday and the conditions have to be right.
My commute is 30 miles a day on a rural A road, cruise 50-60 mph with the occasional overtake and my long term average is about 34 mpg.