After the War, in January 1919, No. 1 Australian Auxiliary Hospital gradually closed down. By February the ANZACs were gone. The House was sold to the local County Council and became a sanatorium for the treatment of tuberculosis and in later years other lung and respiratory conditions. It progressed to a General Hospital in the late 1940s under the NHS and then a specialist heart and lung centre, where pioneering transplant surgery was carried out in the 1970s and ‘80s.

Today, in partnership with Royal Brompton Hospital, Chelsea, Harefield remains a centre of excellence for medical care, in particular heart and lung medicine and transplant surgery.