Aviattic’s catalog shows no 1/32 RFC/RAF roundels, and Pheon has been hors de combat (one hope’s only temporarily) for some time now. If you can find it, NovaScale’s 1/32 Pup sheet has wing roundels of approximately 47 mm diameter. I don’t know the correct diameter for the Camel, as I sold my last kit and aftermarket decal sheet ages ago.