Ahh the old DPF issue.
I bought a MK2 Leon 170 TDi, a few years ago.
It was by far the worst car I have ever had. I tested a 140, and wanted a bit more grunt, so a 170 it was.
I was not told about the DPF, no mention of it from the salesman, I believe as VRSTU alludes to, they have to tell you about the DPF and its suitability to your projected use of the car.
The DPF is not suited to school run usage, it needs to generate the high temps that only frequent long runs will give.
The car had all extras, including the unwanted DPF. I had major problems with the DPF (tractor sounds, warning lights etc), and I was using it properly, it gave very poor economy (41-42 max if driven like a granny), and eventually I cut my losses and went for an ED30.
Seat didn't want to know, wouldn't even investigate, the car when I sold it had 5k miles on the clock. so it was still virtually brand new.