(10 Jun 2014, 6:56 pm)Dan wrote The Angels may be different then, perhaps?
I know there's definitely some that alternate between CCTV and advertisements. Another screen for Next Stop Announcements?
Sometimes on the one I get to school the CCTV screen just shows the 'SONY' symbol. I would assume this is because it come straight out of the depot and hasn't yet loaded. On the rare occasion that I get the 21 back home - the screen is always showing what the cameras are picking up.