Hi, I am trying to find an older children/teen fiction book probably published in the 90’s. It is about a group of classmates being blackmailed by the caretaker’s son, who knows each of their secrets. They group together to seek revenge and get their secrets back. There is an Asian or Indian girl, who cheated on a test, a girl with a white streak in her hair from a scar, the bully refers to her as ‘bird crap’ and I think her name was Rosa? A boy called Liam, nicknamed ‘mouse’ and the son of a famous footballer player, who is new to the school. The caretaker’s son loves battenburg cake, which he calls ‘window cake’. They all get their secrets back from him in the end, and confront him, meet his mother, etc. I have hunted the internet, but can’t find any sign of it!