Reduce / Hide gap when site title/tagline not shown?

In regards to: https://rijidijo.managedwp.com.au/ as I have elected to deselect the 'Display Site Title and Tagline' option (the info I need is already in the header image. As you can see there is still a white 'gap' where this information is normally contained - between the header image and the menu/slider. How do I adjust or remove this gap please? Thanks