Distorted picture/no picture on channel 1

[Cathyjardine180]

Hi. I am currently having issues with channel 1/bbc1. The picture ends up distorted and also disappearing completely. This is happening on my living room TV which has the sky box and also in my bedroom which doesn't have a sky box. Does anyone know if this is an issue with sky or will I need to get an engineer out to check my aerial etc ? Thank you 

[Mark39]

Is there any error message on screen? Tune to BBC1 and then check your signal strengths, by keying Services > Settings > Signal on your remote. The white part of all four bars should be at least half way across and not vary much.