The error log may or may not be of help depending on what the issue is.
How comfortable are you editing files?
It looks like in a default configuration, your feed is coming from
wp-includes/feed-rss2.php
You might be able to edit that and see if you get any changes or where the extra html is coming from. One caveat, you’ll need to disable Magpie cache on the RSS feed, which is actually pretty easy.
To do that, open up (around line 645 in WordPress 3.6.1)
wp-includes/rss.php
and change
if ( !defined('MAGPIE_CACHE_AGE') ) {
define('MAGPIE_CACHE_AGE', 60*60); // one hour
}
to
if ( !defined('MAGPIE_CACHE_AGE') ) {
//define('MAGPIE_CACHE_AGE', 60*60); // one hour
define('MAGPIE_CACHE_AGE', 0);
}
Then you should be able to edit wp-includes/feed-rss2.php
though you may need to do a full refresh on your browser with each change.
This about all I can do with the info given. A bit of a mystery, I’ve never seen a full html page added to the end of an RSS feed before (only error messages). If it makes a difference, it looks like the latest post (Our Team) is what’s being added.
A second caveat – I’m assuming it’s the rss2 (default) feed. Given the link you provided, it should be.