Fraulein Mueller - S1.E5

Jane wants to become a nun so Baines sacks her and brings in stern German matron Greta Mueller, who is a tyrant and tells Sarah where Diana hid the Porsche.

Tom cons Baines into making him the head of the Residents' Association and gets up a petition, which Baines thinks is to get rid of Diana, so he signs it. Actually it's to get rid of Greta, so he is forced to fire her and reinstate Jane.