I was seeing something similar on a restricted (50mph) part of the M25 at the weekend. Sat at a steady 50 and got nearly 50mpg out of my re-mapped 225. Sadly, most of the time, when you're on boost properly 70-80mph it dips down to 34mpg-ish. Round town though it's actually no worse than my cammed 172 was but that would hit 45mpg more easily on a steady run. I used my 225 Trophy as my daily car but I will admit to not using it mid week other than two evenings and at the weekend. I commute by bus/train to work so still don't do many miles in it.
Is that purely town driving or a heavy right foot? I do recall seeing someone on MeganeSport.net who had done a track day and had theirs showing 4mpg.
I commute in mine. I'd go as far as to say it's good on fuel when cruising, you plant your foot though and you can see the mpg counting down.
I averaged around 25 on the school run in stop start traffic travelling around 14 miles, would get 31 on the motorway in my stage 2 megane, that was with a faulty thermostat!, now 33 on the school run and averaged 44 on 100 mile run to Blackpool and back, revs higher now too:cool: