I've got a Zetec S, had it around 2 monhts, and have done 1800 miles.
When I first picked it up I got around 47mpg with mixed driving. 50/50 town & motorway.
Now that I'm using it to go to work, which is 90% motorway at 75mph with a bit of stop/start due to traffic conditions, I'm getting 51mpg per trip computer. (I still open it up for overtakes/slip roads)
I did 460 miles on a full tank then it took 41 litres (9 gallons) to fill it so about bang on 51mpg real world as well.
I fully expect that 55+ would be achievable with less traffic/70mph.