Actually Glen, I am not totally convinced that the longer necklaces in the pair of pics I posted are a match. http://members2.boardhost.com/royal-jewels/msg/1434943465.html Roberts has identified the longer necklace worn for the Beaton portraits as Queen Elizabeth's Coronation Necklace but it seemd to me to be a bit shorter and has larger colletts generally.
If Queen Elizabeth's Coronation Necklace is longer, as I suspect, then nine colletts could be removed, as worn by Camilla.
It took me a long time studying many pics to prove that the Queen Mother wore two diamond necklaces and two pearl ones for her coronation. I have long suspected that some formal portraits were taken the following day and she might not have worn precisely the same jewels. (The official painted portrait of much later certainly shows different jewellery and does not clarify anything for the actual coronation day.)
Compare E (Beaton) and G (coronation day) below here.