Why shouldn't this be covered - it isn't as designed and should therefore be put right, surely. I'd try another dealer and if you still get no joy get onto
Renault Customer Services
I've had no trouble whatsoever with any problems I've reported on the bus including a rattling steering wheel cowling which they happily removed and re-fitted without charge or hassle.
The only time I can remember paying for anything was last year on the E Class Merc I had which at the time was a year old and was making noises from the front suspension when manoeuvring at low speed. They discovered that inner wing lining was rubbing on the tyre on full lock because it had come loose, they charged me because they said it must have been accidental damage - turned out that wasn't the problem and they never did solve - I gave up. My god, some of you think Renault service is bad - don't ever buy a Merc