She died in 2000. (Not to be confused with the American oil/watercolor
painter.)
Her late stepdaughter was the British novelist, poet, essayist and
biographer Penelope Fitzgerald.
http://en.wikipedia.org/wiki/Mary_Shepard
(includes links to three obits)
Excerpt from one obit:
In 1937, Mary married the editor of Punch, E.V. Knox. By then she had
already launched her own modest career in collaboration with P.L. (for
Pamela) Travers, author of the 1934 "Mary Poppins" and all its
sequels. Travers had wanted Mary's father, who by then had illustrated
"The Wind in the Willows" and the Winnie the Pooh stories. But E.H.
Shepard was too busy to oblige. Then Travers saw a hand-drawn
Christmas card she liked. It was by Mary Shepard, then 23 and just out
of the Slade School of Art. Travers imagined the nanny looking like a
doll she pulled out of the attic: a wooden peg Dutch doll with painted
black hair and turned-up nose. Shepard bought a similar doll to pose
by her drawing board as she made line drawings for the eight Mary
Poppins books published from 1934 through 1988. The Disney motion
picture somewhat changed the period of the story, but adapted
Shepard's costume and style for Andrews' character. The author and the
artist had many discussions of what the "almost perfect" nanny was to
look like--including whether her feet would be in the ballet fifth
position as a straight line or fourth position at right angles. The
author won in the book versions where Mary's feet are at right angles;
but the artist won out in the movie, where Poppins' feet are heels
together at a 180-degree angle.
And, from another obit, which I can't find right now, Travers was
quoted as telling Shepard: "Mary must have no figure."
Lenona.