You do need permission if there is copyright material (licensing is required) - also crediting for airplay so royalties can be paid to the song owners on any general broadcasting or recording into shows. If in the Uk, and the songs are copyright and published - you probably would simply license the material used on the CD through the MCPS who represent writers and publishers. Go to their website PRS/MCPS alliance. It depends who has been assigned the collection rights to a song. If you have trad. material obviously you are just paying yourself.