Yes, I believe the Sky LNB's are a clip in type and not the standard 40 mm collar. Check the connection at the LNB - try moving it about while someone watches the TV. I don't know whether you can see from the display if the problem occurs with Vertically or Horizontally polarised channels, or even which frequency is affected. The polarisation is selected by either 14 volts or 18 volts fed up the LNB cable, and the frequency band is also split in two and determined by a 22Khz signal, so a fault can just affect certain channels.