Ok here it is guys, in this instant of test, car's computer showed 38mpg average. Sounds good to me, not 40 or 47 but good.
However test was 200mls motorway at 70mph.
50mls out of suburbs x 2, onto 60mph B road.
Filled up tank noting gauge reading just touching red with 33 Ltrs.
Spare 11.16 Ltrs in can for back up.
All came to £60 for what, 9.71 gallons. I remember when it was 25p/gal.
So 33 Ltrs gone in 235 mls....32.369mpg.
Added rest, had to get off motorway..44.16 Ltrs gone in 320mls..32.95mpg.
Both equate. So I got 32mpg....quite a surprise not 38 as on cars screen.
Maybe I should get a smaller car, eye right. I do/spend this every week. Retire, that's a good idea.
Goggs.

 

I remember when it [petrol] was 24 old pence a gallon, old pence [twenty shillings or 240 pennies to the pound] that is, two shillings, or what is now 10p per gallon. I remember .. .. they reduced the tax by 4% per gallon that year, its up to about £2.70 a gallon now.

TBH googs, that's about the size of it with these van's, I get about 36 ± at 70ish on cruise on a long run with the 2.8. Mind you that's the car's telemetry telling me not a tank to tank, or measured quantity. I did do a test that gave 50MPG at 50MPH. I suspect if you started it and left it parked outside your house you'd get about 50-55MPG from the EVIC, its like all engines from a 50cc to a 5,000cc its as good as its revolutions ÷ weight - your test does show the discrepancy between the car's calc and the real world calc.

Winter, we start the car & let it warm while we scrape the widows, statistically we do shorter on average journeys in the winter. The oil is thicker and the engine takes longer to warm, the engine runs richer fuel anyway in the winter, cold lowers the tyre pressures in the winter. My winter point is that at sub 10°C your car will do about 40% less MPG in its first mile of every run when cold.

Apart from the obvious good maintenance, 5 lbs extra per tyre .. pressure, and keep the boot off are the two biggest items you CAN control in terms of fuel consumption.