TV In Space podcast features the Doctor Who series 12 episode:

Spyfall Part 2

In this episode, we discuss our thoughts on why a part 2 can be hard to write. Ian discusses the TNG episode Time’s Arrow and how that compares to Spyfall part 2. We discuss our thought on the new incarnation of the Master and try to figure out if he comes before or after Missy. We also discuss the pros and cons of introducing historical figures into Doctor Who.