My runs to Heathrow and Wycombe and back in recent weeks have easily attained 55mpg with a mixture of 60 roads and motorway. I always use Eco for the long trips, as i prefer the way the cruise control reacts as opposed to anything else. I might leave it in sport to go on the 120 mile round trip on friday and see what i get. I find that any long run of any sort seems to do a DPF regen, it just likes the opportunity i guess.
She is approaching 10k miles now though, whereas sub 3-4k the economy on long trips was poor. I do notice though, that i've changed my driving a lot since getting the golf. I read the road a lot better in anticipation, coast up to junctions where before i was off the loud pedal and onto the brakes etc. I'm not afraid to hoof it though. :p I'm at the point now where she is attaining good economy, and can get somewhere near book on a long or summer journey, as opposed to the howling 40-44mpg i was getting on early runs.