Hi all,
It seems it was the splitter causing the problems. It is an intermittent fault but I have watched it (using the signal monitor) runing at 12 dB happily then suddenly dropping to zero for anything from 1 to 30 seconds.
Have changed the splitter and retuned the Receiver and (uising one of the bands) the separate smart TV. The new LNB has been delayed but hopefully I will have eight bands on the Gigablue, four on the VBox and one on the smart TV before the end of the weekend.