assuming theres around 5 litrs left in the tank when you fill up thats around the 22 mpg mark. if theres a lot of stopping and starting in your town driving than that will be the main reason, also if you carry a lot of tools around all the time and the dogs and being a heavier estate model it all sounds about right to me for town driving. remember weight needs more energy to move it about.

i've got a 2000 2l 5dr zetec and get 31 mpg with mixed driving. no motorway, odd bit of dual carriageway, open road, town, pootling about and giving it death and when i do get on the motoway and dual carriageway i cruise around 80 which doesn't help lol. found my mums old 1.8 (same year) did about the same but wasn't as quick!