I have averaged 17.5 mpg over 1 year. That included a 3000 mile trip in Europe mixed driving, 3000 motorway miles and about 4000 mixed town and spirited driving (weekends).
Going to work, which is a 2 mile open road then 3 mile town journey i see an average of about 16mpg, bearing in mind this is a from cold start so running rich for the first part.
Motorway i would expect 22-23mpg.
Town, average about 15. In slow crawling traffic it can be 11-12mpg.
Fast A road, 17-18mpg.
Hance i averaged 17.5 over 1 year (10,000 miles).
But if you get a milltek, its worth every penny. I dont do many miles cummuting and use an old landrover for half of that. So its only expensive when i want to have fun or take her on a long journey (holiday).