The UDF was something Andy Tyrie came up with in 1969, up around Magilligan... (He probably couldn't spell UDA right). It lasted to the degree that it made it to the list of official acronyms provided on the CAIN website, here.

I heard of the set of initials (vaguely) when I was growing up, like Den, in the midst of the conflict. They were never a player in the bigger picture, and it was soon forgotten about, once they got the spelling right.

brucie, on the other hand is just a fool, who spends his time on this forum, apologising for getting it wrong for some reason or another.