Think we have found a solution to this..is was the Sky box..! it needed an update to cope with the HDMI interactions...should yo need to this is how to do it..
1) Switch the box off at the mains. [Don't switch off by pulling the power cable at the back. It's not a clean switch)
2) Pull the viewing card.
3) Push and hold in the backup button on the front panel whist switching the mains back on. Keep the backup button held in for 25-30 seconds. If your TV is on you'll see an information screen telling you that the firmware is being updated. The update takes about 10 minutes.
4) Once the update is done the box will switch itself to standby. Switch off again at the mains, then put the power back on. It will take a minute or so for the box to reboot before the green light can be switched on. Go put the kettle on
5) Switch the box on with the remote and flick through the channels until you get an onscreen prompt to put in yur Sky viewing card. At this point your update is complete.