Had an email from the dealer that inspected the rust on wifey's car today, as below.
Our Bodyshop have made their assessment of the issue with your cars paintwork.
To be covered by the anti-perforation warranty the defect has to present as a hole coming from the inside of the
affected panel out.
This is not the situation so we are unable to assist under warranty, sorry.
No accident damage, given where it is practically impossible, original paintwork.
So it's not a hole but it is rust bubbling the paintwork, I'm not sure I can be bothered going round the houses with Fiat UK about this, I'll probably get it repaired by a bodyshop and vow never to give Fiat any of our money ever again.
I've just got shot of my Ten Year old Subaru Legacy, now there is a car that led a hard and uncaring life on Forest tracks and though that had led to some serious repair bills the bodywork was absolutely perfect.