[interestednovice]

Interesting, so normally it is a rare Freeview outing of BBC One Nightlight (effectively)!

No, because that is only going out on the SD transponder at 28.2e which is the one that satellite viewers are receiving. 

Having a red caption saying about buying a new receiver would look odd and cause confusion on terrestrial where there's no SD closure scheme

True, but I assume they simply don’t insert the red screen blanking for that feed - it would be “network” from London, totally unblanked.

Not quite Nightlight, but region-less as Nightlight is.