I have a small issue when my web page gets below a set width and the menu is supposed to switch between horizontal to a mobile vertical menu.
It seems that before the menu would shift everything on the page down to make room..but at this time the page stays as it is and only part of the sub menu is visible..
Almost like the z-value is behind the other content..
I have looked through bat cant see where the issue is ?
If possible could someone take a quick glance, as you may be able to point me in the direction of my error

The issue can be seen here : http://www.yarakbirdsofprey.co.uk/index.php
just resize browser down until it switches to mobile, you will see the menu is behind the content .
Many thanks
Carl