I did a bit more research (I have something else to do I don't like starting):

there's a searchable list of violent deaths in N-Ireland at the CAIN site (here). This site doesn't have the names Allan Bell and Sean O'Malley from the DT versions, but it has:

Isaac Scott (killed 10. July 1973)
Sean McDonald (killed 25. August 1973)

The dates fit well enough, so obviously the names are the correct ones. I always liked that song thinking it was an invented story with invented names (though based on similar incidents), but I hardly can describe you my feelings when I saw these two names coming up on my screen, I started crying for them.

____________________________________________________ (some minutes later, as in a new post): Mick, thanks for the praise, but before I cannot post tunes I am not in the same class as Alison is.

Wolfgang