Remove additional navigation area

Hi there,

How do I remove the white space above my header where the additional navigation usually goes?
I am currently using the ‘fixed header with social icons and additional navigation’. I want to use this one because of the size of the logo.

If it is easier to use the small fixed header and change the logo size that would be great too. The logo starts off too small and goes too small when scrolled when I use the small fixed header.

The website is
http://nonsurgical.org.au/

Thanks!