The Sixth Doctor and Constance (and Flip)

There’s a gap at the end of the previous section, in which it’s assumed that Peri’s story has ended, and this era picks up with the Doctor meeting Mrs. Constance Clarke, a code-breaker from Bletchley Park in WWII. Once again, she’s a capable woman with a strong personality capable of standing up to the Sixth Doctor’s bluster, and in this case Constance has her own agenda. After several stories, Flip reappears, letting us know what she’s been up to in the interim. As of the time of this writing, their final status is unresolved, but hopefully we'll get more with them at some point.