Tonguez
A suffusion of yellow
Apparently theres copyright issues regarding the Rani, which mean she is unlikely to ever return. The character was owned by husband and wife Pip and Jane Baker both of whom are deceased without heirs. Neither Big Finish nor BBC are sure who holds the rights
I was tongue in cheek with my Rani comment.
Supposedly the Mrs. Flood actress previously appeared on Eastenders back in the 1990s when there was a one-off Dr. Who crossover episode for Comic Relief or another similar charity. Might simply be a sly in-joke about that history with the 4th Wall break rather than anything more complex.
But then, it could be something.