Banner & Menu Width

@James: You can try adding in the following CSS in “Appearance => Theme Options => Custom CSS” box.

#header-image,
#header-menu {
	margin: 0 auto;
	width: 1190px;
}

@media screen and (max-width: 1224px) {
	#header-image,
	#header-menu {
		width: 1024px;
	}
}
@media screen and (max-width: 1060px) {		
	#header-image,
	#header-menu {
		width: 900px;
	}
}
@media only screen 
and (min-device-width : 768px) 
and (max-device-width : 1024px) 
and (orientation : landscape) {
	#header-image,
	#header-menu {
		width: 960px;
	}
}
@media screen and (max-width: 960px) {	
	#header-image,
	#header-menu {
		width: 700px;
	}
}
@media screen and (max-width: 767px) {
	#header-image,
	#header-menu {
		width: 380px;
	}	
}
@media only screen 
and (min-width: 480px) 
and (max-width: 767px) {
	#header-image,
	#header-menu {
		width: 440px;
	}
}
@media screen and (max-width: 479px) {
	#header-image,
	#header-menu {
		width: 300px;
	}	
}
@media screen and (max-width: 320px) {
	#header-image,
	#header-menu {
		width: 95%;
	}	
}

@James: I see that your site header images matched the same width as the menu. You don’t need to disable responsive design. As the CSS above is for responsive design only.