His former wife Hilary Kay Brewer, 67, of Knowl Gap Avenue, Haslingden, was also convicted of indecently assaulting the same victim when she was an adult at the Brewers' then family home.
The abuse by Sir Cyril was said to have taken place at Cambridge House Children's Home, a privately-run care home which closed in 1965, and the council-run Knowl View residential school, which shut in 1992.