Been trying out different driving styles for the 4.2 sc, for mpg e.g
grandad style/ slow and easy and getting 16.5 average for a thousand miles local driving occasional motorway runs etc
Then faster driving but not screwing it and amazingly its now doing better mpg, the computer has rose to 16.9 overless than 50 miles !.
Question is why ? As nursing it to me would equate to better mpg.

Not much in it either way by the sound of it... Have you tried steptronic where you decide when to change gear?

Try any of those three methods and you still won't beat it... You'll never quench it's thirst!

It's all about where the torque is. Tends to be where the engine is pretty efficient.

As you increase the revs the engine hits it's sweet spot so you get more pull for the fuel going in.

That said, if you work it too hard, you will use more fuel than you need to.

Tricky balance.

Some say most fuel is wasted accelerating back up to a desired speed after slowing down, so best to get to desired speed again as quickly as possible and thus take foot off throttle earlier. I'm not so sure. 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport