best ever was a trip to cambridge @53.3 mpg ( really tying for economy on that run)
worst is the school run in a morning when its minus 10 like last year which gives about 28 (using journey computer)
always mid to late 30's on average overall.
got 29.5 mpg towing 1500kg caravan to the lakes from Derby & 30mpg on the way back.
checked the computer with a brim to brim & it was reading under by 1mpg but if you factor in the miles covered on the trip meter is probably 2 or 3% optomistic than it kinda balances out.
once its rolling in 6th it's quite easy to keep the swingometer near the 50mpg on the motorway. more so at 70 than 55.
I do drive fairly lightly overall though & always anticipate islands etc & try to coast (foot off) up to junctions etc. rather than brake hard.
I would proably have an M3 but couldnt live with 20mpg. I just couldnt. That would be like paying £2.70 a litre to me