car is covered with a 7 (?) year anti perforation warranty, provided you service booklet has been stamped to say it has had an annual inspection at the time of service.
Without this, you're screwed.
Provided it looks like there has been no stone chip, leading to corrosion, then you will be covered under warranty.
If there has been a stone chip present, and then it corrodes (this happened on my Zed roof), then you're screwed and its for your own account.