Without going into the accuracy or reasonableness of the copyright claim I can throw light on some of this. In the beginning, there was Francis McPeake, protegé of Francis Joseph Bigger and Roger Casement. He learned pipes (see Francis O'Neill: Irish Music and Musicians) and at some stage played with a Welsh harper. He also took to singing to his pipes. When his two sons were growing he apprenticed one (also Francis) to the pipes and the younger (James) to the harp. These were the members of the McPeake Family trio who won the Llangollen Eisteddfod in the fifties. James (Jimmy) still survives and is the person named in the copyright statement.

After his father's death and the adoption of the family formula by his brother Francis' family (and after Francis II's death by his son Francis), Jimmy's musical direction altered. He was and may still be a member of the folk group Barnbrack, whose most famous song is the inane "Mickey Marley's Roundabout"

Presumably Jimmy was his father's legatee in the matter of the copyright - or else there's been some family arrangement - or maybe Jimmy's more opportunistic than the rest of the, now very extended family.