Bespoke
These pieces were individually handmade by Juliette Designs, in London, England. This is the atelier that makes the replicas for "The Crown", the later series of "Victoria", and many other TV shows and movies.
Juliette Designs is at www.stagejewellery.com and www.royalexhibitions.co.uk.
(I am not affiliated with them. Just a loyal customer.)