2013 Cooper D smoke

[this is my username]

I've got a 2013 Cooper D Clubman with about 80k miles on it, I've driven 20k miles in the 12 months I have owned it.

I've noticed it producing some smoke when under hard acceleration, but hadn't given it a huge amount of thought. Today I was driving in traffic and noticed that it was producing noticeable amount of smoke when accelerating / decelerating in 2nd gear - smoke was grey rather than black.

It's not using any oil or losing coolant.

My previous car (diesel Smart ForFour) didn't smoke at all.

Any comments / thoughts about whether this is normal for a Cooper D, and if not what I might need to investigate?

Thanks