Hi there, just done some tests on mine
Im getting 27mpg half town driving, half motorway, and the other day did 400 miles to a tank on a motorway trip, which worked out at 33mpg, this was all done using proper the proper grandad style

stuck to 70mph, no hard exceleration ect.
To be honest the auto box is bad for consumption around town, but better on a run. Until last week it had been a while since i drove an auto round London it is easier the only side effects are the consumption and my terribly withered left leg
If you do alot of town driving a manual would be better.
this week i did mostly town driving and have done about 270miles the fuel lights not on yet but it will be soon

having said that it will cost about £60 to fill up so not far off yours.
Give it a service, if you havent already, and drive it like there is an egg under the throttle!!!
cheers maggs