John Bryce replaced Brian Clemens and Albert Fennell as producer for the start of series six. By the time Clemens and Fennell returned, three episodes had been filmed: two 90-minute episodes, named "Invitation To a Killing" and "The Great Great Britain Crime", as well as a standard-length episode, "Invasion of the Earthmen". These were considered to be extremely flawed episodes; they would likely have been scrapped, except that time did not exist in which to film new episodes and still meet the American contract. Hence, "Invitation To a Killing" was heavily edited and had several new shots filmed to become "Have Guns — Will Haggle", while "The Great Great Britain Crime" was heavily edited and had some old footage from previous episodes added, as well as some new footage, to become "Homicide and Old Lace". "Invasion of the Earthmen" was slightly edited as well. No known copies of the original versions of these episodes exist.