The song lyrics are about seeing something one really wants (God in this case), then not being able to see or experience it ever again. The "gaffa" of the title and chorus refers to gaffer tape, the strong matte black tape used by technicians in the film and concert industries.
The B-side is the original mix of "Ne t'enfuis pas", only released on a handful of singles in late 1982. "Ne t'enfuis pas", which is misspelled on the original sleeve as "Ne T'en Fui Pas", means "Don't run away" in French. In some countries, the B-side was "Dreamtime" (which originally appeared as the B-side to "The Dreaming").