Windscreen seal failure

In that group I see someone else said they think it happened because they pressure washed the car too hard so would seem the likely cause but not one you could prove once you’ve driven the car away from the dealer. The other week whilst washing my lcv I noticed a scratch on the wheel arch just a couple of days after it had been to the dealer. Now it could have been anything from someone walking past it at my work or on my driveway, myself when cleaning although I’m very cautious in what I do using new cloths etc or could have been the dealer. Sadly you just can’t prove it or accuse anyone.