I have had a chance to think about the shape of the body of your piece. It would seem to be the bowl of a rather large punch ladle. Alcoholic punch was a very popular drink in Britain during the 1700s. Many ladles of various sizes survive. Often the handles were made of twisted whale baleen, a brown material somewhat like horn.
Baleen rods are part of the mechanism for straining food from water in certain whales.
Baleen handles are brittle and prone to breaking and disintegration. If the handle became irreparably damaged that would leave a silver bowl. One popular form of silver ladle was a shell shape with a pointed spout at the end. You can see the form in this punch ladle from the collection of the Royal Ontario Museum, which has a later replacement handle of wooden doweling. Be sure to enclose a stamped self-addressed envelope large enough to include any photos that we must return to you.