That is because the 1989 coin is on a different page.
The 1966 to 1984 had the Arnold Machin Obverse of Queen Elizabeth II
The 1985 to 1998 had the Raphael Makleouf Obverse of Queen Elizabeth II
The page you are looking for is this one .....
https://en.numista.com/catalogue/pieces2561.html
Regards Mike
Master Referee - See my profile for what I collect.