May contain spoilers:
.
,
,
,
In Series 9 Episode 3, a patient arrives at the surgery with a small bird (a finch) in her pocket.
The bird finds its way onto Martin's desk. He spots it there and promptly tosses it out of the window.
"Careful Doc," says the woman, "he can't fly."
The truth of her statement is demonstrated by a sound effect of the almost weightless bird hitting the ground.
Later in the episode, the receptionist is on the phone talking to a man she addresses as "Mr Chegger".
A few moments later, she addresses him less formally as "Scott".
Later still, he sees a patient called "Paula Kemp": no, I don't get it either.
Ada? Yes, I would have got that - but her name was Paula.
Perhaps she was a red herring?