Start-up smoke on a 2010 1.5dci megane coupe

Hi all, i ain't had the car long, but every time i start the engine after it's cold, i get quite a big plume of whitey/blue smoke out the exhaust, it smells a bit too?

It was apparently fully serviced before i got it? private sale, so can't be 100% sure. No warning lights on dash, etc... & after a couple of minutes it's gone..

I have given it a bit of blast down the motorway, to clean things out too (you understand), but a week later & i still have the smoke!

Any ideas on my course of elimination, thanks

Start-up smoke on a 2010 1.5dci megane coupe