Hi Karl...welcome to the Forum
Is the car predominantly driven around town or is it worked on long or fast journeys?
Only, if it's smoked around town it leads to carbon build up in components such as EGR, injectors, piston rings...all of which can lead to the symptoms you describe.
Running fuel additives to clean the engine and a good blast to clear it through may sort it.
Let us know how this progresses.
Cheers Trevor