Here's the blurb for No Trouble for Susan, the eighth in the series and the last of the not-so-hard-to-find books. It's also one of my favourites. As I've mentioned before, this book is often confused with A Job for Susan as the gang spend Christmas in Wichwood Village and help out a local shop keeper. But they also help out at the local theatre. This is the story with Timmy the Terror and his gang. It's a very enjoyable story and includes the disagreeable Mrs. Weatherby, who is angry after being sure that she lost her brooch at the book shop, claiming that it is very valuable and somehow accusing Susan and the Carmichaels of being incompetent.
However, when the brooch turns up at the theatre and Joe the policeman phones her and suggests offering the cousins a reward, she changes her tune, claiming that the value is only sentimental.