HMRC have issued a new Charity advertising notice. See https://www.gov.uk/government/publications/vat-notice-70158-charity-advertising-and-goods-connected-with-collecting-donations.

Its virtually identical to the last 2002 edition and there are no policy changes. It covers the operation of the concessions that apply to donations as well as badges etc. Charities would be as well to print out the new version.