Does anyone know where I can find a correct Harvard reference format to upload on Mendeley Desktop and use it with the Mendeley Word plug-in?
It seems that the ones available are not correct.
You can preview a style by hovering over its name:
Once you've found your style, right click on the "Source" link and click on "Copy Link Address". (e.g. https://www.zotero.org/styles/harvard-cite-them-right?source=1)
Now in Mendeley, go to "View > Citation Style > More Styles... > Get More Styles" and copy/paste the link in the "Download Style" box (and click "Download")
Then go back to the "Installed" tab and select the style you just downloaded and click "Use this Style":
(You may have to restart MS Word)