i was on the motor way doign about 58 when ireset my meter and i think it went upt o about 92mpg, then it started to drop off and settled at 48, but when you just reset it it constantly shifts, even a slight dab of the throttle put the mog into a tail spin, but the longer you leave it for the more stable the result. the main problem is your town driving, if its mainly town then your down below for all the stop start, irst and secont gear, possibly hard accelerating, my problem is that non of the lights in my are are on flat land they are all on hill, either half way up or at the botom of a vale, so when you stopp at them your going up hill with alot of strain ont he engine.
if you done more motor way miles you would see a drastick increase in your mpg.
try friving every where are 1500 rpm and changin up idealy at 2100 but no more than 2500 and keep to the speed limits, and take a while to get to those revs will add loads, but you could be late.
also check your tyre pressure,s they should be about 28-30psi, all round for normal use and upto 32 on the front for motorway. also take as much crap as you can out your car, if you have any thing un essential in the boot, leave it at home. i'm tempted to remove the back seats as an experiment o see how much difference they make ot my economy, all i use them for is a boot extention any way, only had people in them 3 times in the past year.