I can now see some weird paths in your page source:
<!-- jQuery -->
<script type="text/javascript" src="//http:www.britishsteam.com/smartmenus/libs/jquery/jquery.js"></script>
<!-- SmartMenus jQuery plugin -->
<script type="text/javascript" src="//http:www.britishsteam.com/smartmenus/jquery.smartmenus.min.js"></script>
...
<!-- SmartMenus core CSS (required) -->
<link href="//http:www.britishsteam.com/smartmenus/css/sm-core-css.css" rel="stylesheet" type="text/css" />
<!-- "sm-mint" menu theme (optional, you can use your own CSS, too) -->
<link href="//http:www.britishsteam.com/smartmenus/css/sm-mint.css" rel="stylesheet" type="text/css" />
You also have tried to include the SmartMenus code twice:
<!-- SmartMenus jQuery plugin -->
<script type="text/javascript" src="//http:www.britishsteam.com/smartmenus/jquery.smartmenus.min.js"></script>
...
<!-- SmartMenus jQuery plugin -->
<script type="text/javascript" src="//http:www.britishsteam.com/smartmenus/jquery.smartmenus.js"></script>
It’s needed just once.