I'm going to say no, though I don't drive the 1.6. I say no, because I'm sure I have read on this forum that owners tend to get nearer 40 around town.
As ever, its all down to state of the engine, driving habits, tyres, tracking, balancing blah blah blah
31Mpg isn't terribly bad, and wouldn't make me think there is an issue, but do you think there is an issue?