Pretty much the norm. My Mrs could only get 21/22 mixed driving.
The odd long run helps improve it, just pottering around chokes them up. I've had about 11mpg from it. My st24 was more economical and my L200 sees 32+ so they're piss poor, one of the main factors for us getting rid. We could afford to run it like that but didn't see the point when the Mrs sat in traffic most of her journey. Can run her fart box fiat nearly a month on a weeks fuel in the st170. While it's not quick the chassis is great on the little fiats.