The world’s oldest uneaten chocolates are over 100 years old. A tin of chocolates from the coronation of King Edward VII from 1902 sits in the St Andrews Preservation Trust Museum. – WTF Fun Facts
Source: https://www.thedailymeal.com/cook/oldest-box-chocolates-world
Your statement is untrue. There are quite a number of the 1900 Boer war tins you show, complete with chocolate made by either Cadburys, Frys or Rowntree. I have a 1900Boer War tin complete with a full complement of Cadburys chocolate. I also have some from the 1902 Coronation and other coronations and Jubilees. I wouldn’t recommend trying them. The yeast will have reacted with the air and they will be pretty waxy and awful. Look on auction sites and ebay and you sometimes see them for sale.