[James2001]

Not entirely. They'd still see them during Good Morning Britain and the first half of Lorraine, and the shows in the same timeslots on weekends.

Like in the 90s when viewers in Wales got promos for Channel 4 during GMTV. Which I guess was worse, as Scottish viewers still get ITV2/3/4/Be, whereas S4C likely weren't showing the trailed shows at the same time as Channel 4.