Many thanks for the fast response! Glad it was something simple, and nothing fundamental that was causing the issue.
This does however give us another issue when using the ‘more’ menu on a touchscreen. I removed the url so that tapping the link would open (and keep open) the menu, and not follow a link. Is there a specific url that can be used that will still allow the JS to run correctly, but still allow the menu to be used and display the sub menu until a sub menu link is tapped?