Ah, I read your “This” in your first post as a referring to the previous two posts, ie to Felix’s red painting of decks and David’s suggestion of the use of red lead when doing so, rather than “The above” photo you posted.
To clarify then, CAFO 681/40 refers to the decision to “abolish the use of painted roundels”, not to move them from being directly painted onto decks to painting them on deployable bits of canvas instead as suggested in your first post: “….was soon superseded by painted canvas RAF roundel”. What CAFO 681/40 says should be painted onto the bits of canvas is unspecified: “The necessity for displaying a canvas square and the type of mark to be painted on it, should be decided by the Senior Naval Officer in consultation with the Senior RAF Officer.” However a subsequent order two months later clears up any possible doubt. CAFO 1179/40 (4th July) prescribes what is to be painted on the four sides of the two bits of canvas to be held in readiness: “(i) Single large red spot. Reference letter J; (ii) Two large red spots. Reference letter K; (iii) Single red bar fore and aft. Reference Letter L; (iv) Two red bars fore and aft. Reference letter M. The background to be white in all cases…”