thanks for this.
I still have a problem with 3 authors. Not sure why it is showing their full first names.
Will keep playing with my library to see if I can find a work around.

The Zotero documentation page (see link above) states:

'In this case, you can either go through your library and change all the names that refer to the same person to the exact same form, or you can simply use a style that doesn't disambiguate names.'

I strongly recommend that you identify authors in your Zotero library with names that are entered with different levels of completeness. Edit those author names so that each name matches the entry with the most complete name (first middle and last names). Earlier editions of APA and Chicago style guides mandated (or strongly recommended) this. I'm unsure of the status of that recommendation in current versions. I am not aware of any style guide that prohibits this practice.

For example, the Chicago Manual of Style states:
“Authors’ names are normally given as they appear on the title pages of their books or above their articles. Certain adjustments, however, should be made to assist correct identification. First names may be given in full in place of initials. If an author uses his or her given name in one cited book and initials in another (e.g., “Mary L. Jones” versus “M. L. Jones” versus “Mary Jones” versus “Mary Lois Jones” versus “M. Jones”), the same form, preferably the fuller one, should be used in all references to that author. To assist alphabetization, middle initials or names should be given wherever known”. [¶14.72] (emphasis added)

There are similar requirements with other citation styles. (See: APA Guideline 6.27.)