dma - I have tried turning the power saving off, no change.
Chris - The TV has the latest firmware installed. The sequence of turning on/off the box/TV used to work, now it does'nt!
rpb424 - So I need to remove the HDMI leads, fully power down the TV at the socket, leave a few minutes, then power back on, plug the HDMI leads back in? I will try anything right now! I have done a factory reset of the TV and latest firmware update to no effect, but leads were in.
It seems like some sort of total incompatability between the two sets. None of them individually seem to be at fault. The humax works with other TVs, the TV works with other HDMI devices. Totally miffed at the moment.
Thanks for your replies