Yesterday I made the stupid mistake of putting petrol in my 2007 diesel car. I realised immediately and did not start the engine. We had a garage tow it and drain it. When we went to pick it up they said that they had tested it by running the engine for 10 minutes on their forecourt. We paid and when my husband started it he realised something was wrong - the garage put petrol back in instead of diesel. All the garage then did was drain it and fill it with diesel and then drove it to our house and said everything was now fine. I've always heard that if you start a diesel car when filled with petrol it caused a major repair. What should I tell the garage we want them to do? Will I damage it more by driving it? Will any damage to the engine become apparent immediately or gradually in the future?