Episode 30 - Malcolm Hulke Part 3

After a pretty lackluster Terry Nation month, we return with a pretty impressive Malcolm Hulke month, discussing the "... in Space" Duology of Season 8's "Colony in Space" and Season 10's "Frontier in Space." One depicts the struggle of settlers against a mining corporation, the other depicts the Cold War between two great empires, and they both have the Master showing up a few episodes into it and proving what an opportunist he is. One of these stories ranks as one of Hulke's best; can you guess which?!