If the lights on and a good run at high revs won't clear it you need to visit a garage who will hook a computer up to the car and do a forced regeneration
My mileage has just dropped dramatically from c.20,000 to c.10,000 miles a year, the diesel has gone and been replaced by a petrol motor
It'll be lovely feeling the heater work in the winter[emoji1]
Regards all
John