You need some U.K.-specific knowledge, which is that CEEFAX went off air in 2012. If you see a screenshot of genuine CEEFAX (not one of the several modern things that pretend to be teletext) it will be from before 2012, possibly from long before as it was a service embedded in analogue PAL broadcasts that was capturable as page text (with all of the control characters) by BBC Micro users (who had bought the Acorn "Teletext Adapter") as long ago as the early 1980s.
