Complex sentence: Other work has included the literary adaptation "The Cazalets" for BBC One in 2001, the latter of which was co-produced by actress Joanna Lumley, whose initial idea the adaptation had been.
Split into simpler sentences: Other work has included the literary adaptation "The Cazalets" for BBC One in 2001. This programme was co-produced by actress Joanna Lumley, whose initial idea the adaptation had been.