Polly Price didn't think it was possible for her actress mother, Arabella Diamonte, to be any more embarrassing than on the trip to San Francisco last summer. That is until she agrees to take part in a television programme called ''Celebrity Home Watch'' and a camera crew arrives at their home to film. Her mother lacks volume control at the best of times, so this is truly a reality tv nightmare - with no escape for Polly! Dee Shulman has created a real hit for young readers with her charming full-colour illustrations and interactive concept.