The third story would have been Mission To Magnus, seeing the return of the Icccccccccccccce Warrriorrsssssssssssssssssssssssssssssssss and Sil. Again I received this at Christmas 2017 but it remains unopened so this 40-year-on listening will be a premiere for me.
The fourth story in the season was going to be a three-parter by Robert Holmes provisionally called "Yellow Fever and How To Cure It", though I strongly suspect this uncharacteristic story title would have been changed for broadcast. It never got beyond drafts and has therefore never been made as an audio adventure.
Instead, I decided that I would replace this story with the unmade Hartnell story "The Masters of Luxor", which itself was replaced by the original Dalek story in 1963. This again was bought specially for Christmas 2025 so I have never heard it, but I have read the script book which was published in the 1990s.