MCOL default judgement submitted last year but I no longer want to claim it

[jpfullknmr]

Hi, a little over a year ago I bought a used vehicle from a car dealer for £5000. The dealer claimed the car was spotless (as they always do) but it turned out to have some faults including the windscreen washer pump being completely broken and not functional, making the car unroadworthy. Since it was within my 30 day buy period, i rejected the car to which the dealer stopped responding.
Since september (date of purchase) until december (date on which the default judgement was submitted) I didn't use the vehicle, but after december I realised that I cannot fully proceed with claiming the money and returning the vehicle due to his company being an LTD and having nothing registered in its name.
Since that situation has been affecting me negatively mentally (having to deal with the fact that I 'lost' £5000+£500 on the MCOL claim), and the fact that my commute to university, which was supposed to be 40 minutes by car, became 2.5h long with busses+trains, I fixed the car myself, insured it and started using it. My parter was supposed to use the car to get to work as well so it was frustrating that we both were out of money and out of a convenient way to commute.
I did not pursue anything in that direction since that time, however a couple of weeks ago I have been served with papers regarding his attempt at removing judgement. In his defense, he has stated things that are complete lies (saying there was nothing wrong with the car, that he was not refusing communication etc.), and I prepared myself, including receipts from mechanics, quotes from the Ford dealer and statements made by the ford technicians regarding the state of the car (it was involved in an accident that was not registered - not mentioned at the point of sale but quite obvious by looking at it if you have any experience with cars, which I did not have). I'm well prepared for the court hearing which is in December.
My question is, what is the possible outcome of the hearing? Am I going to be 'punished' in any way for using the car despite asking for a refund through MCOL? Is it possible to claim for losses regarding the purchase of the car i.e. costs of repair, court costs? In the case that it is awarded/judgement is held up, does that change the situation with the fact that his company is an LTD?