Send it to them just in case, I’m sure they will appreciate the gesture even if they do know.Update: Managed to get a hold of that PDF, and the last chapter deals with Richard James and Harriet Ellen Vanstone from page 58 and forward. It mentions their daughters, but stops there (I suppose it's because of privacy protections). Do you think DDP is aware of Carol Bell? She's the author of this text.
I was surprised they didn’t know about my tip, it comes right up when you first start googling the name. They are very swamped with work so it may just be that they don’t have the time for some of the groundwork right now.