Personally I'd check your cam chain tensioner, if it's not all the way out or close to it, then you know that your cam chain itself is fine!
Same for you Simon, check to see where the tensioner is on it's travel before splitting the casings for something that really won't be needed.
FWIW, I've never heard of cam chains being treated as a consummable (except on some REALLY old Hondas with chocolate camchains and cams), on newer bikes it's really not something that I'd think of going wrong really, unlike the tensioner itself!