I was only a young boy at the time, but if memory serves, Danger UXB was about about a unit of bomb disposal experts during the second world war. The UXB meant 'Unexploded Bomb'. As the name suggests, it was their job to defuse German bombs that had failed to detonate. I think one of the actors from Brideshead Revisited was in it. Can't remember his name but I remember having to beg to be allowed to stay up and watch this show.