Dang, nice. I get 25 - 27 every single tank. I have never experienced anything in the 30s, let alone 40s.
What model/trim do you have? How fast did you go? Cruise control? Any mods that would aid with MPG?
What the heck is a motorway?
2017 Infiniti Q50 Red Sport 400 RWD, Iridium Blue/Black leather
1999 Nissan Maxima SE, Icelandic Pearl White/Black leather - Supercharged 4AT (322 WHP / 307 WTQ)
2001.5 Audi S4, Santorin Blue Pearl/Black leather - Bi-Turbo 6MT AWD (300+ BHP)
2003 Acura TL Type S, Metallic Gray/Black leather - 5AT - Daily Driver