[interestednovice]

Thanks for clarification 

So why does it vanish at night when BBC news us simulcast and nit reappear on Saturday until 1000 etc?

Possibly just because it would “cover up” the BBC NC lower thirds and look a mess?

Or perhaps  technical reasons, where BBC One does effectively “close down” overnight and the simulcast is “run by” BBC News, so play out is a bit different to normal as the feed is produced straight from NC and just put straight to air by BBC One?

Or even perhaps platform rules, where Sky especially may not be happy with a captioned channel 24/7, so they have to have some hours without. They deliberately make these the least watched overnight hours, perhaps. Rather like BBC Three’s phantom existence on satellite after it closed.