From someone who is a diesel owner, a Fiat diesel engine fitted in my Saab 9-3, concerning a forced regeneration should there be DPF issues. Please be advised, if the garage carry out a forced regen, then it is highly advisable that a oil and filter change is carried out immediately afterward as diesel can be dumped into the sump mixing with the engine oil and raising the oil level to over capacity.
I got into the habit long ago of removing my EGR and MAP sensor every six months to carry out cleaning/maintenance. It's an easy diy job on my engine, but I accept that it isn't always the case on lots of engines, especially diesel engines in small vehicles where there may not be much room to work. Also, many owners won't have the mechanical aptitude to do the work and so often have to resort to garages to do the work.
Ideally, diesel engines need lots of good, long extended runs to keep the DPF and EGR/MAP sensor soot free. If you're only ever going to do round town runs, you'll get problems because you won't be doing enough to burn the soot off during an active regeneration. Twenty odd minutes at 2.5k revs on the motorway usually does the job. Also, fuel, I never, ever, use supermarket diesel anymore. I converted to Shell Nitro Diesel over two years ago and it makes a very noticeable difference.
