Thanks for the reply Peter I'm aware of the functionality you described.
However when you have set up a custom list is there a way of using it to achieve the result in my origninal post? Eg. notice how the number 3 in my original post has the next tier of the list (letters) starting directly from that point, rather than in your example where every list item in the first tier of the list must have contents, followed by the next tier items.
I hope that makes sense, basically if I have a list of questions labelled 1. 2. 3a. 3b. 3c. (but no 3.) I want a list that enables me to insert answers for all these questions.
Edit: Also another question, when you make cutom lists as you have described, they seem to only be available for the document they were created in, is there any way to make a global custom list that can be used in all Pages documents?