Lord Geoffrey Greystone was the owner of 64 Carlysle Street.
Lord Greystone had been married to Lady Edith Greystone until her death in 1906. They had a daughter named Annabel. Some people thought he had married Lady Edith for her money, but he claimed that he had loved her.
Lord Greystone was unaware that his daughter Annabel knew the Marquis of Rostock, in reality an alien called Roztoq, until the First Doctor brought it to his attention. He invited the Doctor, Steven Taylor and Dodo Chaplet to his house to confront Roztoq.
To Lord Greystone's horror, Roztoq brought a silver thing with him that he used to possess Annabel. The Doctor encouraged Annabel to fight the thing that was possessing her, and she was freed from it. (PROSE: 64 Carlysle Street)