Sure, but the "See it, say it, sorted" announcement is played over and over ad nauseam on the train; it's not just a sign. It's the national rail equivalent of "mind the gap" on the tube, which is also said over and over again. In the case of the tube it makes a little more sense since the ridership is changing significantly at every stop. But on a 4+ hour ride up to Edinburgh, it is pretty redundant to make the announcement every minute or so.
"Mind the gap" announcements used to exist only where there was a huge gap on curved platforms. These locations still use the authoritative, male voice.
Playing the woman's voice version at every station started about 15 years ago.
It's a thing our governments do to ensure that we are all slightly traumatized by the possibility of terrorism at all times. They make us afraid to make us easier to control.