You probably have little to worry about with the tougher MOT.

I understand the tougher MOT is to root out vehicles which have had parts of emission control systems altered (removed, gutted, bypassed). IE DPF's, Adblue, EGR valves etc.

If your car hasn't had the emission systems altered from factory spec, then I don't think you've anything to worry about.

I understand the M.O.T for diesels is getting tougher and diesel cars are now being demonised and sales are going down. When I bought my used diesel 3 years ago I was on the bandwagon of people switching to diesel for the mpg and thought the newer diesels were ok with the cleaner engines. Now I suppose if I trade it in I'll get a very low trade in value and if I keep it the M.O.T will be much harder to get through. Think I made a mistake getting the diesel.

Realistically the main issue will be 'how much do you use the car for short and/or start-stop journeys? If you don't use it at least weekly on a decent blast down a fast-moving road for a reasonable distance, to give the DPF the opportunity to passively or actively regenerate, then you might face some serious costs on that score. If not, then you should be ok for a few years if its well maintained and all the fluid levels (incl. adblue) at the correct levels.

From looking at a reasonable number of other people's MOTs (including when looking for second hand cars and 'being nosy' looking up SLO's/BBD's ebay/AT suggestions), most failures seem to come from (especially within the first 5-6 years of a car's life):

• Tyres worn down to below the legal minimum;
• Headlight aiming mechanisms not working correctly;
• Badly worn brakes and suspension components.

Its often because people scrimp on maintenance and drive them unsympathetically that they fail MOTs (and often).

Many others have suggested running diesels on super grade (only difference is the extra cleaning additives, not any increase in 'cetane' rating equivalent to the octane increase in superunleaded petrol) if you do a lot of urban, slow speed driving and have had (or the car is known for) DPF problems.

If you do do predominately low speed urban driving with little chance of passive DPF regens via longer runs on faster-flowing roads, I personally would get rid of the car after its 5-6 years old tops unless you can guarantee its previous history, you've had no issues at all with any of the emissions systems and/or you need it for towing. You've had it for 3 years, so you should have had a reasonable time to see what problems it has had, if any.

Next time - don't believe all the sales blurb/hype - look around for information on the internet, including here: its all easily available and, if you look in the right places, far more independent, accurate and useful than (in my opinion) anything you'll find on a manufacturer's website, in a glossy brochure or especially sales talk at a dealership.