Header doesn't match preview!!!!!

I’ve just installed the theme and find that the horizontal menu in the header is underneath the header image. The image of the site shown in the preview on the www.ads-software.com site has the menu bar above the image. I can’t see anything obvious to fix this and it looks awful the way it is.

The site is https://www.myagasaga.co.uk

Someone else seemed to comment on this about a year ago with no response!!