Re:
Sadly, Rudi would spin in his grave at what his engine has become..
The whole point; the ethos of the diesel engine was a simple, reliable engine that could run on any fuel available in localised, non-grid, disconnected parts of the world.
A lot of people have converted their supply to part-oil, part vegetable, or biodiesel, etc fuel and suffered no ill effects to the motor.
The very fact that there is a fuel we call 'Diesel' to use in a spark-less combustion motor is complete anathema to the creation of the engine. It is the fuel which should be moved away from, not the engine.
The more we scrap 'Diesels' all we are left with are coal/gas-burning 'electric' cars and fossil fuel burning petrol cars. Although it does not suit the government contracts or globalised businesses, Diesel engines are probably the best medium-term transport solution for independent vehicles, that we currently have available - they just need to be moved away from 'Diesel' fuel to reduce the particulate emissions.
Smaller growing/farming areas of biofuel, plant oil production, etc within the country (becoming self-sufficient, in a non-European UK) also then reduces the international transportation of crude, the need/number of UK refineries and the number of heavy road-damaging tankers traversing the country. Scrapping a few Peugeots is far less of an answer, but it's a simple populist measure that makes the decision-makers feel good while achieving precisely nothing.. So to be expected from politics, sadly.