I have no idea of the source or origins of the choker. But I would have thought it would be in Queen Mary's Jewellery Inventory - before 1932. The picture is a case of mistaken identity, in my view (and needs to be ignored in Roberts). It is hard to know if Roberts simply accepted the Royal Collection entry, which is a shame because of the flaw with the years. I'm convinced it's not the chain-link bracelets/choker. It may or may not have become the bracelet worn by the Queen Mother. I cannot really tell.