I never got more than 45mpg out of mine, as opposed to the Panda 1.2 that gets 49-50 on average. Theres an interesting factor here to do with engine power. The greater the engine power the less you have to boot it up hills, and overall on a long journey I have found that a 1.2 gets closer to book expectations than a 1.1 and a 1.6 even more so, then as the power makes less difference the 1.8 and the 2.0 I've owned were similarly dissapointing. 1.6 being the best, powering a saloon.
You might find a 1.2 sporting does better mpg, if they ever did them. I've lost track. But people normally fill up at the 290-310 mile mark with the Sei, if they don't the little yellow light comes on.....