I have read this, when it came out and I was a librarian, but only as an adult and therefore I remember very little about it.

Nevertheless like the Edward Gorey covers that grace many books in this series. this kind of made me gasp, because that's so deeply wrong! They're illustrated within and usually without by Pat Marriott over here, and while Gorey is fantastic of course, Pat Marriott is Joan Aiken's older work to me. (Her younger work is often illustrated by the brilliant Jan Pienkowski.)

Wolves sequence illustrations therefore all look like this sort of thing.