TwistedTory, just wanted to add that media loads somewhat differently and more slowly in the TV app compared to the old (better) Video app. Please ignore if you already know this or have already tried it:
First, in the TV app, tap the "Library" triangle in the upper left corner, and a drop down menu should appear. It takes a minute or so, but eventually your iTunes media should show up. Mine shows up at the bottom of the menu as "(Name)'s Music."
Second, tap that link to your iTunes media and it takes you to a new screen. Now in the upper left corner a "Shared Library" triangle should appear -- tap that and another drop down menu should appear. Again it takes a minute or so, but eventually headings for your iTunes media should appear. For me, these headings include TV Shows, Movies, Home Videos . . . Tap your headings, and you should see your music and videos.
Again, sorry if you already knew this or have already tried it.