We never learned Mrs. Warbut's first name, let alone her maiden name. But as played by Avis Bunnage, I think it's reasonable to suggest that she was related to the Rumpole family.
Perhaps she was the younger sister of the twins Horace and the Village leader known only as "Number Two".
- 'Inspector Morse' - "The Settling Of The Sun"
- 'The Prisoner' - "Chimes Of Big Ben", "Once Upon A Time", & "Fall Out"
- 'Rumpole Of The Bailey'