Id definitely try an mmi update. If you've bought it within 30 days from a dealer then they should fix this for you for free. As you're still entitled to a full refund within 30 days.
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I think the Cambelt needs changing at 120k or 5 years which ever comes first
You could always get a garage to do a forced regeneration. Alternatively you could remove the dpf to clean it and refit it to see if that fixes it. Or buy a new one.
Or take it on a really.good run to see if it clears the light.