@John I have read this thread with great interest. The elusive 4:2:2 clearance of H264 content eh.
I see several people think that there is something special about the GTCombo. There isn't, other than it has a media player that is attempting to clear the Chroma feeds through that media player. Unfortunately the specs of the GT does not have the requisite processing power to do that on a continuous uninterrupted basis.
So. This is tried and tested and works for those who want to clear H264 4:2:2 feeds.
Any E2 receiver will pick up a 4:2:2 feed. It's just a transport stream after all. In order to display it in real time, I use an Apple 4K TV box (the first generation version) using the free VU+ Plus app. Nothing special about the chipset (its an A10X Fusion chip with 64-bit architecture Processor)
It plays both the video and audio feed of the H264 4:2:2 stream flawlessly without stutter, in practical realtime.
You will pick one up a second hand 1st gen Apple TV 4K Box for about €100.