I can well understand and approve your caution.
I have spoken to my eldest sister who is the real family historian. She tells me that after the death of my aunt her children may have given all her boooks to OXfam or were taken by house clearance people. Either could have put it on Ebay. These things happen!
By way of confirming my link with the Whinfreys, I can offer the following. At the front of the Bible there was a list of children, marriages, etc. My great great grandfather William married Eliza in December 1883, and their eldest daughter Florence was born in May 84. This embarassed her later in life, so she changed the marriage date to 1882. My maternal grandmother Ethel was Flo's sister, and her brother William was the one killed in 1916. Eliza Whinfrey died before her son William, before the Great War.
The letter from William's commanding officer was signed Alderson (or something very similar). It is the loss of this letter which has concerned us most.This is what we most regret losing, but we have no oidea what else might be in the Bible.
We are not especially bothered about the Bible itself, but any contents we would be most gratful for.