I'm not sure if she is meant to be a Duchess, but she looks like a painting of the Duchess of Devonshire. My collection of half dolls (also known as pincushion dolls or topper dolls) seems to be expanding. This particular doll is about 4ΒΌ" high, which makes her one of the largest. She dates from the 1920s and she appealed to me because I think she's been nicely painted.
To the side of the half doll is an antique sewing aid, which would have been attached to a belt. It dates from the 1900s and the Dewhurst's bobbin is probably from the same era. The smaller (Sylko) cotton reel is from the late 1930s-early 1950s. Everything is sitting on antique lace.
Taken with Lensbaby Velvet 56.