Apple TV (4th Gen) UK

The main, sorry ONLY, reason I bought the new 4th Gen Apple TV was to access BBC iPlayer. After set up and then accessing the iPlayer app in the App store you get a message telling you that you need to update to the latest iOS. I did this but during the update and after step 1 (of 2) the screen went blank and I cannot tell if step 2 was performed correctly. There were no apparent wifi issues during the update. I now cannot get a home screen on the Apple TV. This is the second unit I have tried after the same happened before. Has anyone else experienced this and if so how did you fix it (if you did!)? Could it be due to using an older (c5 yrs old) HDMI cable? I am using a Pioneer SCLX72 receiver and Kuro Plasma TV, which were (and are) absolutely fine with the older gen Apple TV unit.