Crag / Ben,
I was watching the theme. In our demo the theme is working fine and I dont find any issue.
Take a look: demos.hellothemes.com/hellomix
I was on the store (www dot sugar and spice dot com dot au) and I couldnt see problems with js.
I need more information to try to solve this.
Did you install some extension?
I will send you an email and we share details of this via mail.
When we find the fix we will post here.