Complex sentence: Ransome progressed in her film career playing the female lead in the 1969 film "Alfred the Great": however, her subsequent screen career was focused almost exclusively on television, Ransome having debuted in that medium in the 1967 serialization of "Kenilworth".
Split into simpler sentences: Ransome progressed in her film career playing the female lead in the 1969 film "Alfred the Great". Her subsequent screen career, however, was focused almost exclusively on television, Ransome having debuted in that medium in the 1967 serialization of "Kenilworth".