Make Secondary Nav on mobile show the content rather than show a hamburger?

Hi,

I'm trying to implement a simple top bar on the site to act as a notification (like a popup news banner). I've applied this as the Secondary Nav which works great on Desktop but on Mobile view the navigation items disappear to be replaced by a hamburger.

How can I get the secondary navigation to display on mobile rather than showing a hamburger? The user needs to see the navigation items. You can see this on the test URL.

Thanks,
Nick.