Complex sentence: Youens's television breakthrough came in 1956 when, as a continuity announcer for Granada Television, he became popular for his velvet-voiced tones--a marked contrast to the character for which he would become famous.
Split into simpler sentences: Youens's television breakthrough came in 1956 when as a continuity announcer for Granada Television. He became popular for his velvet-voiced tones--a marked contrast to the character for which he would become famous.