W-nav-menu is preventing my desktop menu in the navbar from appearing

Having a real nightmare with this, my first foray into webflow.

The desktop Navbar for this site had only been built like the mobile Navbar so was totally unfit for purpose. I edited the “Navbar” to create a nice desktop version. All seems fine in the editor, but when I publish the site, it assigns the class “w-nav-menu” to the menu bar, so it doesn’t show. It doesn’t show at all.

I can’t see where to add custom CSS, so I can’t override it. I know it’s this causing the problem, as the menu appears nicely when I remove the class in Chrome DevTools.

Any assistance is welcome!

Here’s the read only link, but I’m not sure that’s working correctly either: