The Grade-II listed property was previously listed in 2016, with its owner saying the proximity to the royal estate had been a big influence.
Elizabeth McGill said: “It’s amazing what a famous neighbour can do to the local property market.
“It has been interesting to see the ‘royal’ effect.”
Treasure hunters should be aware that the historic manor house and grounds stretch for around 3.4 acres, making the search for the jewels much more difficult.
The house itself has a Georgian style from circa 1825 to 1830 and includes a paddock together with a detached cottage which is currently used as a holiday let.
The manor house also comes with fishing rights over a stretch of the River Tywi.
“Nearby Llandovery is soon to undergo some regeneration in the market square area and will become a thriving local town once again.
“I am really hoping that the new owner will appreciate the property; it’s a grand property, but a very warm and engaging home. It deserves to be loved as much as we have loved it.”