will never buy French again. It looks nice, has alot of toys but the engine is awful.
Bizzare as that engine has won nothing but praise in both Nissans and Renaults. Its not amazingly economic as its used as a sports engine in smaller cars and a bit of a power unit in the larger ones. I think the engines amazing, delivering alot of low down torque meaning you can also change early. I have no idea how your only managing 36mpg, my 180bhp 3.0 V6 dci Grand Espace is managing that, hell my old 1.6 VVT Petrol Scenic managed that.
I would of said perhaps you weren't used to driving diesels and needed to adjust your driving style but your ownership history says otherwise. Thus from an engine that should be getting 40mpg+ without issue, your engine has to be ******. Theres a billion things it could be. If under warranty get Renault UK involved.
The turbo doesn't deliver a kick back in the seat style of driving, if you want that get a 230 etc.