There's no mistake in 99, Suki. Most of the entries I've received so far have got it right, so I don't think I've made it an unreasonably difficult clue.
On a different subject, would anybody care to suggest a theme for the next quiz? So far I've done British placename, famous women, & foods. Any ideas or requests, anyone.
Thanks as always to all who support Macmillan Cancer Support through these quizzes.