As a paying client and paying for ongoing support every 6 months, how do i change my fav.icon in the address bar / for bookmarks?

As long as you have ftp access, just upload a new favicon.ico file in your public_html folder.

Do you need technical support?

You can obtain support via [url="https://www.invisionpower.com/customer/"]the client area[/url], or you can try to obtain peer-to-peer support at [url="http://forums.invisionpower.com/index.php?showforum=308"]IPS Resources.[/url]

I would recommend submitting a ticket in your client area if you require technical support.