Greyish smoke when starting

I have a 2013 Ford Galaxy 1.6 Ecoboost 6-speed manual that has done 347,000 km (215,000 miles). Last winter, I noticed a small cloud of greyish smoke every time I started from cold but once the cloud has dispersed, no new smoke formed whilst driving nor when idling. I assumed it had to do with the cold and wet winter here in Belgium. This week, however, it has been sunshine and 20 degrees but the cloud is worse and also when starting from warm. But only if I have left the car for a bit, say one hour. The cloud is big enough to almost engulf the car but once gone does not come back.

I think I can hear funny blowing sound when driving, certainly if I am close to other cars or a wall but it is very faint. The car consumes a little bit of coolant but has done so since I bought it two years ago so that has never worried me as such given the age of the engine. The smoke started this winter. Car drives fine, idles smoothly, no obvious oil or coolant leaks. I have it serviced by Ford once a year and it recently had its annual MOT, which does not say much I know but they are stricter here in Belgium than in the UK and if the car had had a serious leak they would have failed it.

I am thinking exhaust. I will have it diagnosed by a garage but wondered if anyone here had any ideas?