Some people really dont want a CCJ, as that stops you taking out loans etc. It is all that happens in England as well if someone doesnt pay after loosing a court case.
Sale of goods act doesnt apply to private sales. That is why traders say you are safer to buy for them, i.e. you pay a bit more for the car but you have peace of mind that if something is wrong, the dealer has to fix it.
The only way you can go after the seller now is if he lied to you or said something that was not true. It is useful that the add was on fleabay, as the fleabay rules say that all faults have to be listed. It would be very difficult for him to prove that some of those faults were not that at the time of sale. However, it sounds like you have decided not to go down this road.
Good luck with getting it sorted. Once you have done so, it will be a nice car.