John,
Just encountered your queries. I met Dr. Felipe Tredennick in 1987 in La Paz when my wife and I were researching Butch Cassidy and the Sundance Kid's adventures (and death) in Bolivia. He opened some doors for us.

William G. Tredinnick (spelled variously in different records) is mentioned in Mark Stead's 1936 book Treasure Trek, and as well in Col. Percy Fawcett's 1935 Lost trails, Lost Cities, though not by name, just as a Cornishman in trouble with the law, and in Stratford D. Jolly's ca. 1930 South American Adventures. WGT got mixed up in one or more expeditions to find the mythical Jesuit gold treasure at Sacambaya. Mythical in that it doesn't exist. He also got in trouble, that is, was accused of a crime, in 1909, though I have no idea of the disposition of the case.

Dan