Dave could it be possible that you accidentally got in your 1.2 insted of your hgt like you said you didnt put your foot down so you wouldnt notice lol
sorry m8 but my 1.6 isnt even that good and drive like an old man
i got about that when i drove from home (essex) to coventry BUT i was driving at 65mph constantly anf no traffic...
generally i get 23-25mpg.. and country lanes seem-20mpg
although i believe that 40mpg is possible (done it) its only on a motorway at a constant speed... i never ever come close on a combined figure, my mums c-max diesel gets nearly 70mpg at a constat speed but averages 50mpg...