You may be able to confirm this Mike - but I seem to remember Bob Thomson telling us that Harry's brother was a singer and, according to local talk, a better one than Harry (such claims aren't always reliable of course, "you should have been here last week!!" is a fairly common statement).
One of the aspects of the tradition much neglected is songmaking within the communities.
We first noticed it with Travellers - still practiced up to 1975 with Irish Travellers in London; but here in Clare, we have been staggered at the number of songs that have been made in the past on local subjects and have never moved out of this area because of their local nature.
One of the riches subjects of local songs was the land-wars that took place from the 1880s right up to independence in 1922.
A 90-odd year old singer told us last year that "If a man farted in church, somebody made a song about it".
For me, it stresses the importance of folk songs as carriers of (quite often unrecorded) history; one of the reasons why I so vehement that they should be treated differently from other types of song.
Jim Carroll