What is Kitty's Last name is Tracy Beaker Returns?

her last name is Allen she also might be related to Rick he is like a Big Brother to her and Tyler and is extremly over- Protective of them especially Kitty as when Sapphire Calls Kitty a Headcase he get's mad and says ohh she's not a Headcase do you still get a Say you don't even live her this shows he looks out for he is also seen holding hands with her outside when there is a fire in the attic x