I'm not sure if this helps but as, I'm sure you are already aware, the YouView box seems to be in "continuous" (!!?) contact with a YouView server somewhere.
It updates firmware across the net without local intervention.
I tried the iPhone app to add a couple of recordings (it does not handle series yet!).
My box was in standby state. When I turned it on a minute or so later and immediately checked the schedule, the new entries were in there.
By the way, I rarely use the YouView box from one week to the next (preferring the t2) yet it has updated the firmware a couple of times in the interim, without intervention from me.
I can't say whether the box kicks in in the middle of the night, can't be bothered to stay up and keep watch.
I just tested it with the box turned on and it seemed to take about 5 minutes before 2 scheduled items reached the box. They were triggered from my iPhone a few minutes apart but appeared together.
So I suspect the box polls the server periodically.
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