My racing campaign is sponsored by several companies, and in return I carry their company names and/ or badges on the mainsail. How does this affect my permit and ability to wear the Blue ensign?
It is difficult to see how this is anything other than advertising, and as such incompatible with wearing a Privilege ensign. You should not therefore wear the Blue ensign when the branded mainsail (or other sail) is aloft but may do so once the sail is stowed (and you have hoisted the burgee to the masthead).