Toseland, you drive like a chronic twunt, i'm not surprised in the slightest that you can't get it past 50mpg. 
Seriously though, averaging over 50mpg isn't hard if the car is healthy, just takes a bit of steady throttle control and forward planning in traffic.
The maf does make an emormous difference to efficiency by nature, as without it the ecu can't achieve accurate fuel metering to match the air available, as you say. Very interesting theory, i might have to test this one out. I wonder if it's because without a reliable reference to air temperature it has to assume the worst and beef up the pre-iniection to ensure a complete burn of the main....
Seriously though, averaging over 50mpg isn't hard if the car is healthy, just takes a bit of steady throttle control and forward planning in traffic.The maf does make an emormous difference to efficiency by nature, as without it the ecu can't achieve accurate fuel metering to match the air available, as you say. Very interesting theory, i might have to test this one out. I wonder if it's because without a reliable reference to air temperature it has to assume the worst and beef up the pre-iniection to ensure a complete burn of the main....