Im not really an expert but have spent the last week wrestling with another of Flythemes templates I might have the reason but not necessarily the whole answer.
The menu is there on mobiles its just been used below the slide picture.
The reason for this might be that your logo image is 114px deep and the theme was designed for a logo 49px deep and is pushing the menu bar down.
Quick solution would be to resize your logo image. Other solutions would be to change the position of the mobile menu in the stylesheet (Just a guess).
Thank you to your Support team for their help.
I have sent email with url and admin login to “support@”
url is http://www.independentcelebrant.org
I have sent email with all the details and admin log in.