@ Thomas Harvey
Is this mainly short journeys or have you done any longer distances yet?
No car will perform well economy wise on short journeys ( apart from electric powered ones!)
It will improve as it beds in, but there’s no need to keep the revs so low. In fact to get the best from the engine as it gets older, you should occasionally rev it to around 3500 and higher as the miles increase, once the oil is warm of course.
We had your car’s predecessor, the 1.4 TFSi S tronic and overall we only got 36.1 average over the 3 years, although it would often get over 40 on a long run.
Around town on a cold engine, 20 to 30 sounds about right.
Forget the EU official figure of 47 or whatever it is.