I have done 10,000 miles in mine in the last 5 months. 60 mile commute (round trip) B roads, A roads and some dual carriageway gets me 30-31mpg. Motorway miles typically 29-30.
However recent weather has dropped it to 28.5
Shell V-Power helps, BP Ultimate is about the same, Tesco Premium stuff is quite good too
When having a spirited drive does it drop it to 20ish
The engine is superb, the sound it lovely, the popping exhaust is fantasitc. Handling is great, good practicality (2 bikes in the boot no problems), 2 kids in the back (not with the bikes!)
You don’t buy an ST for the fuel economy…