Changing the subject somewhat.
My GTD arrived today and on the first initial 20 mile spin it to holds up well to my g/fs 120d M-Sport (subjectively) in terms of performance and is much more refined than I expected.
The power delivery so far has surprised me as it doesn't suffer with that horrible soft off boost delay, sudden delivery and narrow powerband that previous diesels I've driven had and that the 1er still has to an extent, the power curve is much smoother and more progressive...