The biggest downside is that while there is a bibliography, there's no citations and I get the impression that some of the more intimate details are actually just family lore and legend passed down the generations. The author is, after all, the current Countess of Carnarvon and so this is essentially her husband's family history. As a genealogy enthusiast myself, I can certainly appreciate the incorporation of stories passed down generations but it also means that I always take family lore with a grain of salt. I wish that it was more clear about what information came from what sources. That said, to be fair, the author prefaces the book by making it clear this is "not a history" or biography so she is upfront about it being rather more like a family story.
But if you think that means it's all about gossip, you'd be wrong. Almina's contribution to society, especially during the war, was very admirable and I enjoyed reading about her personal growth and professional growth during her efforts to help people and support the war. This, along with the detailed account of the discovery of Tutankhamun's tomb, which was funded by her husband, were definitely the highlights of this book.