My current car was purchased 2nd hand with 36k on the clocks. It has now done 76k, 95% of which has been short 10 mile journeys with only 2-3 miles of that on a 50 MPH dual carriage way. Only had 1 DPF issue, which was when the EGR failed and it couldn't regen. Once that was fixed the car was able to do a regen and been fine since. That happened in May last year when the car had circa 65k on the clocks.

In short I wouldn't worry about it too much.