Apple sneaked out a minor update of the Apple TV software this week updating to v4.4.1. However I noticed that my Apple TV was stuck at v4.4 and refused to see the update. I have been running a beta version of v4.4 so I assumed that was the problem though the summary for the update makes me think otherwise:
Addresses an issue that required a small number of Apple TV units to be connected to iTunes in order to complete the update.
To fix the problem I had to connect the Apple TV to the computer running iTunes using a micro USB cable (without the power cable) and perform a restore. Luckily there is not much local configuration data on the Apple TV other than my Apple ID and password so a reset is a quick solution.
After the restore from iTunes it is now happily running v4.4.1.