I have agreed a deal on a used Maserati Quattroporte Diesel and paid a £1000 deposit (to hold the car until collection) part of the deal was a full MoT. While taking it to the MoT, the driver put £20 of petrol into the tank and started the car - within moments it was switched off but having run it for 30 seconds or two minutes the petrol will have potentially affected the fuel pump and injectors. The dealer phoned and advised me that this has happened and that they are sending the fuel pump and injectors away for pressure testing and obviously changing all the filters and they suggest a DPF removal and clean as well.

Do I accept the car in full working order, reject it and walk away or try and negotiate a lower price?