Data in foreground of tv picture

There should be an option on the remotes to disable Closed captioning (subtitles).

This seems like a subtitle problem as I had the same problem last week and the problem was caused by me inadvertently pressing the subtitle button my remote.Have you got a Subtitle button on your remote.

I agree with the previous answers, this could be as simple as you accidentally pressed the Subtitle button, but I would also check the settings menu using your remote because captions could be enabled for BBC channel only, if that is possible at all. Anyway, it may be worth checking.