Complex sentence: The broadcast of "Limbo" and "Know Thine Enemy" was initially postponed: they were due to air on 9 and 16 June 2007 respectively but did not air as scheduled.
Split into simpler sentences: The broadcast of "Limbo" and "Know Thine Enemy" was initially postponed. Both episodes were due to air on June 9 and 16,2007 respectively; but did not air as scheduled.