I would definitely check Morley’s website. They have strings for Grecians and might be able to provide more info on the harp’s history.
Oops, posted that before reading all replies. Do let us know what the Morley folks have to say about the harp.
It looks beautiful from the pics. I have an early 1800s Dodd single action I got off eBay ages ago and sadly it is not in the best shape. Someone painted gold over the original gilding.