lol
i don't find it funny jonny, if you read first post in this thread, i mentioned how many miles i'm getting in one full tank, which works around 26MPG which in my view is far low!!
i'm only getting 5-6 miles per liter and the picture i posted was to give idea about revs which i normally drive on. i hardly rev over 3000 in any gear
if you're not revving above 3K in all respect the engine is working very hard! The idea of the turbo is to provide power with minimal effort but you're not using it at all
i could understand if you had a derv like me as past 3.5K or so the diesels run out of power
get your nose in the engine bay and check for any signs of cracked / split pipes, loose hoses etc
also brim the tank and work out your MPG old skool - don't rely on the computer.