My cheekiness aside .....
.... This is sort of where I am. It's the order of magnitude - and the common denominator is of course CJ, so it does point to driving style.
But to put some figures around it - where LR are citing maximum efficiency for that model at 30 mpg, and manufacturers figures are usually generous, then 38 mpg is 127% of that figure.
I think there are folk on the forum who could confirm I drive 'sedately' and I certainly drive sympatheticly to the engine and running gear..... But I don't get close to a 26% increase on the stated maximum for my vehicle.
So its not that I don't believe it - just that its hard to believe !