Welcome on board from me as well, Damian! And don't worry about your English. One of the nice things here around is that not so perfect language skills never seem to be a problem which is something this non-native speaker still finds very relaxing...
I don't know anything about the pearl choker, but find it somewhat strange that we haven't seen it being worn more frequently, and as far as I'm aware never by Princess Benedikte or Queen Ingrid - which could support Barbara's idea that it might come from Princess Alexandra's husband's family.