Complex sentence: The team performed a simulated operation, replicating the 1952 procedure of lung surgery on George VI, which is believed to have been the first time real doctors and surgeons have been directly employed as actors to ensure realism in a television production.
Split into simpler sentences: The team performed a simulated operation, replicating the 1952 procedure of lung surgery on George VI. This is believed to be the first time practicing doctors and surgeons have been directly employed as actors to ensure realism in a television production.