The main issues here, are that the car you have is secondhand. If it was brand new, then RUK would bend over backwards, they are rEdiculously s**t hot on new car customer services.
The issue with it being secondhand is that it then becomes the problem child of the dealership where you bought it from.
Think of it like this...
When you buy a new car, you are buying a renault product. When you buy a secondhand car, you are buying it from the dealer ship that has it for sale. Thats the way renault customer services will see it.
(I appreciate the car was practically new, but you are not the first owner on the logbook so any argument is void. Its not a new car)