I have also read Black Maria, but then I didn't really read her for a while. Currently, I have Charmed Life out from the library, so I will definitely be reading some Diana Wynne Jones in the next little while in memory of her. It's very sad because I have loved everything I have ever read by her and imagine I will continue to with more reading. The Once Upon a Time challenge is the perfect time to discover her for the first time, read a book by her that you loved, or read something by her you have always been meaning to read.
She will be missed!