This is at the limit of my expertise but looking at the Network tab in dev tools (firefox) I think you might have two copies of jquery loaded.

one from your template folder:

/includes/templates/westminster_new/jscript/jquery/jquery-1.10.2.min.js

and another loaded from your html_header.php:

Code:
<script type="text/javascript">
if (typeof jQuery == 'undefined') {
    document.write(unescape("%3Cscript src='//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js' type='text/javascript'%3E%3C/script%3E"));
}
</script>
If I was debugging this I would remove one of the jquery instances and also turn off CSS/JS Loader.

Beyond that I would probably be stuck.