Low MPG - not brakes binding or Air Meter

Hi all,

having replaced the Air Mass Meter and cleaned the binding O/S/F brake I find that my MPG hasn't improved one jot. I'm getting (on average) 37mpg via the computer and also by calculation. If I drive to work like Miss Daisy all I'm able to get is about 40mpg tops - a mixture of 30mph and National Speed Limits - all at minimal throttle openings and changing to a suitable gear asap - 4th for 30mph and 5th for 40mph etc....

Whilst I had the front of the car jacked up doing the brakes I tried to turn the hub around by hand. With the caliper off it was really quite difficult to turn it round. With the wheel on and jacked up with the pads disengaged from the front disc it was equally difficult - with a big push it would just make one revolution before stopping. Is this normal or do I need to have it looked at by a specialist to discern if there's a problem further up the drive train? Tearing my hair out now!

It's on a Fabia Vrs 2004my with 52k miles.

Thanks

Simon