My XC40

[Quacker]

Originally Posted by Wibblebum

and I'm averaging 31mpg with an average speed of 39mph. Even on long runs, I've not managed anything above 38mpg. The economy on my XC60 D5 polestar was better - I was averaging 36mpg. Hmm....

Are you a particularly aggressive accelerator and braker? My XC90 D5 started off at around 32 with 38 when gently driven. It improved progressively as miles piled on to easily achieve a normal 38mpg with 42 regularly hit and bettered on longer runs in moving but heavy traffic, sort of 'normal' road conditions. This was only after the first 15,000 miles or so.
If it's anything like the Audi Q7 I had, that improved all the way up to 45,000 miles or so. Starting off when new on a tidy run with 26mpg and ending up by the time it passed 50,000 miles easily achieving 32mpg [compared to similar driving in the Volvo getting 42mpg]

I've little doubt that driven sympathetically but not slowly, you should easily hit 45mpg by the time you've driven 15,000 miles or more. Wouldn't be surprised if 50mpg was a regular occurrence. My 160hp 4wd automatic Honda diesel has averaged nearly 49mpg over the last 300 miles. It can reduce to 42 when driven harder though. It has 35,000 miles on the clock.