A quick story about using red diesel.....20 yrs ago My brother had his car seized at Dover port because he had red diesel in his fuel tank, they literally took his car.
He just sat in thier office and said....... “ok” ........40 minutes later they gave him his keys back and handed him a leaflet about the illegal use of red diesel.
The problem was he had his wife and 3 children with him, by taking his car they stranded the full family so they all sat in the customs office, his wife crying and his kids ( 2 of them under 10yrs) running around screaming thier heads off. He just said “how can I leave I don’t have a car and no money”
Ps: They used to dip fuel tanks to check for red diesel but now the can check for red staining in the engine, so if the previous owner of your vehicle used red it will still show that the van has used red diesel even if you have never used it