JoK – 7 minutes ago  » 

To be clear-I used the sky box to make the adjustments mentioned by Graham via the add channels menu. It resulted in the error message that my Sky box isn’t getting a signal. And when trying to reset the Sky box to the original settings ( before the adjustments ) it says No signal found. Does that help?

Have looked and checked the cables a few times, seem to be connecting ok, have removed and reinserted them several times.

So the issue is presumably with your communal satellite source. You need to contact whoever is responsible for the communal services. Generally the electicity supply for the satellite multiswitches is connected to the landlord/caretaker for the block.