Unable to Use Layout Builder

Hi,
I have inherited the maintenance work on an enfold theme that is now running live. WordPress is up to date but the version of Enfold has been left for a few versions so I’m unable to use the Layout Builder.
I know the answer to this is to update the theme to the latest version but in addition to not being able to use the Layout Builder, also the links on the left hand side of Enfold Theme Options are also missing. This means I can’t access the Quick CSS to back this up before I update.
Can you please tell me how I can back up the Quick CSS contents other than copying it from the General Styling page that I can’t access so I can go ahead and update the site.

Thanks for your help

Kerry