That's pretty bad for a 1.0TSI, if it was an S3, I would say, not bad...I guess it's a perfect storm of low city speeds, brand new engine, E10 fuel, and possibly no MHEV (assuming yours is manual?). The worst I've seen on mine is mid 30s, which is literally start, move a few meters, lift off (engine goes off) and it rolls to a stop few meters ahead. I've seen average mpg drop from by 5mpg in a space of 50 odd meters of start stop traffic.
If the car has only be driven in city (20-30mph), you have changed gear between the 2-2.5k mark, been generally gentle with the throttle, then I do not really see anything wrong with such low mpg. However, what 'short term' mpg do/would you get when you go at a constant 40-50mph on free flowing roads for 10-15 mins? You should easily get 45-55mpg.