Teachers Easter Egg - Simon's Real Life Brother

Very near the end of the episode, Simon (Andrew Lincoln/Clutterbuck) is in the staff room of the school and is sitting on a table. Behind him a man sits down and peers over the sleeping old person, then settles into reading a book. This is Richard Clutterbuck, Simon Lincoln's brother (who is a teacher in real life)

At the time of filming, Andrew did not know his brother was there.