The trouble is with modern diesels is that they work well for people like me who drive 500 miles a week in mixed conditions. Two people I know well ignored my advice and bought Audi and VW Golf diesels as 'shopping cars', engines never getting warm. Stratospheric bills on cars that are ultra low mileage and still having (and will have issues). Funny that car salesmen always sold the economy benefits and low tax.
Never mention major engine issues though.
I know of someone who's parents bought a new RAV 4 and junked the engine in less than 3000 miles..
I don't think the issue is with position of DPF it is because engine is not travelling far enough to warm up.
I ran a fiat diesel, an Alfa diesel, 2 mini diesels and 2 Mercedes diesels over 140,000 miles and never had a DPF issue, in fact I never recollect seeing regeneration because the engines were always running hot. I changed to Lexus because of the quality 👍