Yep, I just did the

edge://flags in the address bar.

#load-media-router-component-extension Enabled

And it 'just worked' to my Nvidia Shield.

Well, bugger me!!! Never saw that with my googling.

THANK you VERY much!! 

But, gotta wonder why it is an experimental feature. Perhaps in test mode?

Out of curiosity, how did you find this?

Yep, why the menu item is there when it won't work.....

I also got an answer on a posting on the tenforums site.

Cheers.

Good to know this works

Anyone aware of these sorts of settings to enforce media playback quality settings? Reason I ask is that SkyGo has been updated to run without Flash but it struggles on a ComputeStick that used to run SkyGo just fine. It'll try stream at 1080p, fail and default to the lowest option. If I could set it at 720p somehow across all streaming that happens on the ComputeStick it would be perfect...