First make sure that each box can reliably connect to your homehub, the inter-box streaming should naturally follow. You mention the boxes have problems using VOD (OnDemand), this makes me wonder if your underlying problem is insufficient WiFi signal/speed.
Follow Home > Help & Settings > Settings > Network on the WiFi-connected boxes, and check the signal strength on the top-right, what is it? And are you getting any specific error messages when you try multi-room streaming?
In order to access the boxes remotely to manage recordings, you need to use the "TV Control" app, not "TV Go"
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