I have had my S for 3 months or so and after washing it last night I could see that the paint around the headlights and a little on the back bumper is starting to crack. I will sort some pics later but does anyone know if I can claim under warranty before I ring the dealer and him laugh at me?

 

Your car is four years old or more so not sure if the warranty would cover it. It will lead to corrosion though and that is supported by the anti corrosion warranty.
Give them a call anyway, they will tell you if you have a case, the dealers will not laugh at you as they will benefit from Honda paying them for the repairs.

 

TBH I would have thought with out seeing the car that cracked paint would be the result of an impact and therefore not a warrantable defect.
As regards causing corrosion, yes, but the corrosion warranty is not for corrosion caused by poor anticorrosion treatment, not untreated damaged (for want of a better description) paintwork.

Best thing is to go in to your dealer and get them to look at it and if neccessary create a warranty claim, with photographs to support it.

 

Post some pics. If the paint is cracking on the front and rear bumpers it sounds like someone has had the bumpers resprayed and they've not used the correct plasticer in the paint.