To have any chance of getting redress you may need to resort to legal action, the Consumer rights act 2015, covers this, any item be it sn egg whisk to cars. In your case a recent low milage used car is covered by this, but your car was registered in 2018 if I understand right,
The CRA 2O15, Stipulated that it is a reasonable expectation for any goods, In your case a used car is expected to last for 6 yrs i.e. be of merchantable quality,and fit for purpose.
If within 6 months of purchase it fails ,then you have a right to have it repaired, replaced or a refund, without YOU having to prove anything.
If it fails after 6 months of purchase then it's I cum ent upon you showing proof as to why it failed, which means you have to find an independent expert to examine it and say what the fault is.
In your case, it's a border line case.
My advice is seek advice from Citizens advice bureau, if they say you have a point, then seek a solicitor to seek redress.
First action is make a formal complaint in writing, explaining what is wrong, what you are expecting to happen to redress it, then if they will not accept or agree, then commission a legal to seek an outcome.
I am currently in a dispute for a failed scooter, which is likely to be a long drawn out process, I bought it as a low mileage bike, the engine failed within 4 months 800 miles of use, the scooter was about 2 yrs old. ,but I expect to recover the majority of the expense from the trader.
Do not be fobbed off, be persistent, your claim is with the trader and not Skoda UK,
You may have to take it to the Small claims track at county court to get the matter settled, it will take time, but the Consumer rights act is strongly in your favour.
But you must make a formal complaint in writing ,setting out your position and what action you will take, if they do not want to discuss it.
Ultimately it is that will get their attention, normally it's the threat of legal action that gives results.
Be firm, be positive, take action.