2007 Vauxhall Vectra smoke from exhaust

Sounds like DPF regenerating which is a regular occurrence with a car diesel engine and perfectly normal . Due to the high temp when this happens you get a hot, acrid smell from the exhaust till regenerating complete ..

Thanks for your help But I get smoke coming from under the car , that’s not normal is it ?

The burning at tremendous heat inside the cat convertor of soot is probably what you are seeing or you may have a slight exhaust leak . It is always advisable with a diesel car that is used for short , stop / start journeys to have a belt down the motorway every so often to clear out soot etc . If you still have concerns , take to a garage for checking . This explains ,

https://www.knowyourparts.com/technical-resources/diesel-engines/diesel-particulate-filter/

Sound right , I’m a taxi driver stopping and starting all the time , can I get a DPF cleaner ?

Plenty of options from car accessory shops or the likes of Halfords , for an example .

https://www.amazon.co.uk/Cataclean-Diesel-Catalytic-Converter-Cleaner/dp/B00BFWGI6M

Thank you for your help ??