I have just finished reading Colin Pengelly's splendid biography of Ball, published shortly before his diary re-emerged. In the book, Pengelly bemoaned the disappearance of the diary. It must be upsetting to publish a biography so shortly before something like this comes to light again! Thanks for posting about this (I suspect you also included a link which did not appear on the forum thread – probably defunct). I had completely missed this news item when it came up in 2017. Do you have any idea where the family left the diary? It really should go to the National Archives rather than a regional museum.