Hi,
Well its hard to say looking at your setup because you have jquery files showing not their real path, path rewritten same as if they were pretty permalink.
<link href="http://www.hubbard.co.uk/media/css/cookiesnew.css" rel="stylesheet" type="text/css" />
<script language="javascript" type="text/javascript" src="http://www.hubbard.co.uk/media/script/jquery-1.3.2.min.js"></script>
<script language="javascript" type="text/javascript" src="http://www.hubbard.co.uk/media/script/cookies.js"></script>
<script language="javascript" type="text/javascript" src="http://www.hubbard.co.uk/media/script/global.js"></script>
<script language="javascript" type="text/javascript" src="http://www.hubbard.co.uk/media/script/jquery.js"></script>
<script language="javascript" type="text/javascript" src="http://www.hubbard.co.uk/media/script/jquery.extensions.js"></script>
This is not a part of the theme, so it's probably from a plugin but its over 5 years old, so not even sure what kind of plugin it could be. Lets start by unplugging every single plugin you have, and see if that block of code can be found when viewing the source. If not, they slowly start adding the plugins back one by one and eventually u will find who is disturbing things. You crashed when trying to take off jquerry is because you are somewhere using code that's too old to understand the new jquery . The download manager , the cookie plugin or something with social media is likely the one.
Once we get the plugin removed and modernize things a bit, ajax should start working correctly, because i don't see how its possible for it to work with 3 versions of jquery on the loose.
Thanks,
Nick
Create a new thread and tell me what problems you are encountering and what you want to know. 
There is no step 3 :) 
