In 1923, Mrs H MacAulay-Stromberg bought the Castle from Sir Iain Colquhoun and at last the Castle returned to MacAulay ownership. Under her loving care the Castle and grounds were brought back into good order.

Mrs MacAulay-Stromberg invited Edward Wells to write a history of the MacAulays, resulting in a handsome book "Ardencaple Castle and its Lairds". Mrs MacAulay died in 1931 and the Castle. faced a long period of neglect.

During the Second World War it was, used by the Admiralty as Naval Married Quarters and finally demolished in 1957 to make room for a Naval Housing Estate as the Submarine Base on Gareloch developed. Unable to raise funds at a Local or National level local people could only watch in distress as the Castle came down.