The air Andy sings is the one in Sam Henry which is pretty much the standard one. Since you've mislaid your copy, you'll be glad to know that the air and text of Farewell to Ballymoney is in the Google books partial scan of Sam Henry - cut and paste this link in its entirety.

http://books.google.ie/books?id=aiQ7UAwQgDUC&pg=PA343&lpg=PA343&dq=Sam+Henry+Farewell+Ballymoney&source=bl&ots=tmmqUdUFw2&sig=yGvtqDWHcdMs0c4FyfA1xSPwg-0&hl=en&ei=ilb2TYiWEYy1hAf97LnqCQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBkQ6AEwAA#v=onepage&q=Sam%20Henry%20Farewell%20Ballymoney&f=false

Give my regards to Jo. I tried to help her over chidren's songs in Irish but it's not my field. If there's anything else she's interested in she has my email.

[On another note, I'm told that someone who sang in the sessions in the Harbour Bar in Portrush, died a short while back and they held a fund-raiser for the family a couple of weeks ago - do you know or cany you find anything out about this?]