Well it won’t make some of you happy, but I’m still averaging 41mpg (yes real world calc) on my 6.1 150 manual. And it’s heavy too, with a full camper conversion. Still on original wheels/tyres, so that may be a factor.
Covered 3500m from new and that’s the average. Dropped to low/mid 30’s on a long weekend in Wales due to constant hills and gears changes. But on long runs on motorways using cruise, can squeeze 50-51mpg out of it. Been very pleasantly surprised as I expected less.
I do use use Millers additive every time I fill up though, which might be helping.