Both chainstays, on the underside, where the tyre passes between them directly behind the bb where the tube is compressed. Both have had the paint and laquer crack which is where corrosion has set in.
ChrisF - I expected a response. Even if that response was to say sorry but its outside of the warranty.
As I said, didn't mean to badmouth the brand particularly, I have a different salsa which is trouble free. I only posted it as there is a lot of people view Salsa's system as really good (me included) which may make people consider a purchase but I felt I could add to the thought process with my experience.