Within notebook the alphabet tap has disappeared to make it easier to go to a note within a Notebook

[schwev 1]

Hello, I have notebooks with up to a 1000 notes. Previously it was easy to locate notes within by just clicking the alphabet letters on the right hand side. Now this alphabet has disappeared and I need to search for notes, which is hugely inconvenient and takes up much more time. Is there any way to get the alphabet function back?

[schwev 1]

I should add that I am using a iPad Pro for most of my notes