Whilst Jennifer Lee's storyline makes it clear what her reason for leaving is, I nonetheless think it is a great shame she was never mentioned again given that the series is supposed to be her memoirs. I note Vanessa Redgrave's narration stopped using "I" in all subsequent episodes.
Having headlined a major BBC series it is good to see the real life actor has continued her career after failing to leverage that to break into US films. Intriguing that Karen Gillan managed to successfully leverage her Dr Who fame to make the US breakthrough a few years after Jennifer Lee's attempt.