English Country Blues Band arranged a lot of traditional English lyrics to Traditional American tunes and (I think) still hold copyright on them as arrangements !
Equally so , The Kipper Family 'wrote' parodies f traditional songs which they hold copyright on !!
If the lyrics are 'Trad' then the composer of the tune would have the copyright to the tune , and to THAT arrangement of the song !

Now some one will shoot me down in flames , but thats how I would see the situation !