None whatsoever , I needed to remove the under seal as there are some repairs necessary to the wing by the bonnet locks . The rust is sitting happily underneath the seam all the way along . Plan is to strip the underside of the bonnet, repair where necessary , treat the rust with Bilthamber Deox Gel . Paint with epoxy mastic undercoat from Bilthamber , then paint with cellulose code 66 Valencia Blue and overspray with Bilthamber Dynax UC which is transparent .
The underseal is very dry and crumbly , still a pig to get off though and will need a solvent or similar to get back to original surface
Paul