If you are performing a new version of the original work (a translation, a new musical arrangement, a medley, or using the song as part of the Action Song script, for example) then you will need to contact the Publisher with details of this new version and get permission to perform this particular version.
There is a template letter to send to publishers available to download below. If you’re performing a translation, you will need to send the Welsh translation as well as a literal translation back to English to the Publisher, so that they can approve the translation.
Contact details for many publishers are in the Syllabus, and you can find contact details for publishers on their websites too.