The "Ladies Who Do" are office cleaners. One of them discovers some hot stock tips and they make a fortune. They then make good use of it to save their old neighbourhoods from the wicked developer.
Ladies Who Do is a 1963 British comedy film directed by C. M. Pennington-Richards and starring Peggy Mount, Robert Morley and Harry H. Corbett. It was written by Michael Pertwee and John Bignall.