Apple TV 2 AirPlay & iTunes Connectivity

I have an Apple TV 2 connected to my home wifi network - the same network that all of my other apple devices and macbook are connected to. There is an average 17mbps wifi where the ATV is and the signal strength says very good on the ATV settings.

Despite everything looking good my devices have stopped seeing the ATV on AirPlay and the ATV cannot access the iTunes server. I have tried rebooting, resetting and restoring the ATV, but no joy.

I have another ATV and airport express which I can connect to without problem. I just can't find a reason for this one not being visible and not being able to access iTunes. It has worked in the past and nothing has changed in my home network set up.

Can anyone offer useful suggestions?