Someone I know was advised by his MOT tester to proactively remove the DPF on his van, even though there was absolutely nothing wrong with it. They were touting for the job of getting rid of it, with the promise that it would always pass an MOT despite the emissions then being way too high, just as long as he keeps getting it tested by them.
That's twice recently I've heard of people getting rid of DPFs that have absolutely no issues. Garages are telling people they're a menace that needs to be got rid of as a precaution. I think there's also a false rumour that you get better fuel economy or it goes faster once you chop it out.
We have two diesels with DPFs. Both have just passed 100,000 miles with absolutely no issues at all. Both have exhaust pipes that are still shiny inside. DPFs are a brilliant invention. Some early ones were troublesome, Peugeot/Citroen at least seem to have got it right.
I'd suggest we need the Northern Ireland system - there, MOTs are done at official government centres, not independent dodgy garages. They have no favouritism and don't offer dodgy deals.