High pressure diesel pump failure
VOLVO XC90 II (256)

Hi guys! Would appreciate your opinions/thoughts. 

Story in short: very happy owner of Volvo XC90 (really happy), diesel. Car was bought second hand from volvo dealer, full service history from volvo, 6 years old in Nov 2023, just 50k mileage. 

Problem: high pressure diesel pump died while driving. Volvo on-call was very helpful. Car repaired and I have a bill of 3500 (nearly bankrupted me). Pump/one injector/belt, all changed.

Now I have dilemma: I have no extended warranty, however I know that in case of manufactory defect, warranty in England can be extended up to 6 years (google and gov.uk), but I have to prove that it was manufactory defect.

My question: does anyone heard how common is this kind of failures on such a low milage (50k)? Im using mainly sainsburys diesel (occasionally at asda).

Moving forward: I understand that this is very critical fail and simple exchange of pump wont fix the problem (something about micro-particles within the fuel system as the result of erasure of moving pump components), am I right to be worried?  

Would You consider to send failed pump to specialised centre for expertise (if such kind of expertise exists)? If indeed someone can tell me why pump failed – I may explore legal route with volvo (how far – depends on how critical is this fail).

Thank You everyone.