wrong fuel in an astra

Arrived at a fuel drain in Hammersmith tonight, a diesel astravan had been  filled up with 30 quid of petrol, I had been told that the van had been driven “for a few miles” – whilst draining it down and chatting to the customer he told me it was closer to 35 miles! – and the car had “conked out”, it’s not uncommon that a customer “plays down” the situation becuase they think we might turn down an awkward job, anyway I was there and the customer was stranded miles from home in deepest darkest hammersmith on a sunday night, I did a full drain, tank, filter, hoses, lines, pump – followed by a purge thru tank, lines, filter & pump. I thought it would start eventually (but I was expecting it to fight), amazingly first turn of the key it fired up and ran fine, and the customer was off on his way home 20 minutes after I arrived, I dont know whether to put it down to his luck, or that diesel astras are unbreakable.