Katherine Grayson

Mrs Katherine Grayson (portrayed by Katherine Kingsley) was Frank's mother who appeared in "Fundraising" and "The Exam". She was very keen for her son to stay at Abbey Grove despite nearly every class not wanting him.

At the end of the episode, she is revealed to be in a relationship with Alfie's father Martin. She has a pedigree chihuahua called Coco who she considers a princess, showing more affection towards Coco than Frank. She and Frank briefly live with Alfie and Martin for one episode, despite Martin saying that he was going to move in with her.

This arrangement comes to an abrupt end when it appears that a student may have killed Coco while it was in Martin's care (Coco is later shown to be unharmed). In the final episode "Prom", it is revealed that she has another son named Dean who works at a DIY store that Alfie briefly worked in.