Just noticed rust (bubbles under the paint work, not broken through) on both my front wheel arches, so annoyed I didn't spot it when I looked round the car and god knows how I missed it

.
However after having a google it seems to be a common problem and can be done under the anti corrosion warranty.
Does anyone have any experience or advice they can offer me??
Spoke to my local VW dealer today (over the phone) and they have informed me I need to take it down to be assessed at there body shop (30 min drive).
If its not covered is it going to be an expensive job? 2 new wings I would imagine??
I feel so stupid for not spotting it