OK, my bad ... I have the
stone interior, not
wheat (duh!), but it's just as light-coloured.
I've cleaned mine with Lexol Leather Cleaner (which I had from our leather furniture) and also Meguiar's Gold Class Rich Leather Wipes; the latter are moist wipes impregnated with some "secret" formula.
Both have worked well.
Cheers,
David