Hollamby died of Myocardial infarction, brought about by heart disease, at Red House on 29 December 1999; he was the third owner to die while in residence. His funeral was held on 21 January 2000 in Eltham, with a secular humanist service conducted by Barbara Smoker; the Friends of Red House took over the building's public openings. Ill-health forced Doris to move into a care home in 2002; she died in April 2003. With the aid of an anonymous benefactor, the house was purchased and gifted to The National Trust in 2003, who turned it into a visitor's attraction, with tours continuing to be organised by the Friends of Red House.
