There is a code block missing from the mobile css file which causes the header logo to display wider than the screen on devices between 650px and 1350px. The CSS needs an additional @media in the CSS. I have added this to the Custom CSS and it has corrected the display error.
/* FIX MOBILE LOGO SIZE*/
@media (max-width: 1650px) {
#branding, .topmenu { width:100%; }
#bg_image {width:100%;}
#header-container > div {height:100%;}
}