Thanks for the suggestions on screen as well as showing the Date and Time it also shows Channel Numbers (i.e CH1, CH2, CH3, and CH4) Channels 1-4 are showing live views, channels 5-8 are black and just showing a date and time. I have checked on the Kview app and the only channels that have recorded video are CH1 and CH2.
I will get someone to check the BNC Connectors are plugged into ports 1 to 4.