Thanks Rich,
I bought a [63 plate] 2.0 TDI Black Edition, 150 too, better spec than the petrol one and I'm also only getting around 40/just over, but that's around town, expecting a bit better on longer runs.
Will report back when I've had it a while; I'm considering getting it remapped at some stage, for better torque through the range and a bit of fuel economy improvement