This may help with your research: I found the following today on a real estate site. It suggests that a member of Mount Edgcumbe family built the plantation in the 1700s.
Mount Edgecombe Plantation, Grenada, West Indies:
Mount Edgecombe Plantation provides a yesteryear experience ...Built by Lord Edgecombe of Devon, England in the late 1700’s, in a picturesque, sheltered yet elevated location on the western coast of Grenada this historic and colorful estate enjoys cool sea breezes, overlooks verdant botanical gardens and orchards to the sparkling waters of the Caribbean below.