Google Analytics is saying that:
Status: Tracking Not Installed
on my site, when (as far as I can tell) I have put the tracking code in the site. What do I need to do to get Google Analytics to detect the tracking script is there on my site.
I wouldn't worry about that. Sometimes the Google Analytics Dashboard takes a while to update the status, while in fact the tracking is already working. To be sure, go to Real-Time-Tracking in your Google Analytics Dashboard and see if the traffic updates while surfing your website.
From the sourcecode of your site, the tracking snippet seems to be installed correctly.
You must put the Google Analytics script just before the closing
</head> tag, not at the end of your webpage.
For more information, read Google guidelines to install Google Analytics on your website.