Níl Sé'n La is originally from Tory Island,Clannad has made an arrangement on this song and it was released as LP by Philips Ireland on Clannad 1.The CD was released in 1997 by Royal Records but also states Philips Ireland 1973 for the song.A check of various compilations results in Clannad Music and Tamsin Music popping up,but the year is always 1973.I believe that Blackbird is also one of the sub labels,but I can't confirm this since I don't have the LP.
It's not really important in my opinion since we know that one recording has been used for 3 different releases and the original question has been answered.
