Dear Sally
Yes her parents were Mary Kingwill Doust and John Doust, Mason.
John Doust Died about 1876. On his death cert, present at death was John Parnell son in law. on every piece of paper evidence I have it appears they were married.And Martha continued using the name Parnell. and her death is registered under the name Parnell. But I haven't been able to locate any entry of marriage.