Tadema Gallery is the place to go for great examples of Dorrie's jewellery. The photographs of all the jewellery are exceptional and the site includes not just pieces that are for sale now but an archive of Dorrie's pieces. Jewellery from Tadema Gallery have also been used in the standard texts about Dorrie's jewellery, see Jewelry & Metalwork in the Arts & Crafts Tradition, Elyse Zorn Karlin, 1993, page 85 and Silver Jewelry Designs, Nancy N. Schiffer, 1996, page 101.
For more information go the Tadema's website at http://www.tademagallery.co.uk/.