Mr Dyer said if his family did buy the property in the future, ownership would only be “transitional”.
They would purchase it, hire specialists to conduct a private search for Mrs McKay and then sell it on, he explained.
In October 1970, Nizamodeen and brother Arthur Hosein were given life sentences for kidnapping and holding Mrs McKay, 55, for a £1m ransom, before murdering her.
She had been snatched in a case of mistaken identity on 29 December 1969, with the siblings believing she was the then-wife of newspaper tycoon Rupert Murdoch.
Earlier this year, Mr Dyer flew out to Trinidad with Mrs McKay’s daughter, Dianne, and Nizamodeen showed them on a map where he believed the body was buried.
The murderer’s lawyer, Matthew Gayle, told the Nizamodeen remained willing to come to England to assist with a dig.