I have a HDBaseT extender and with 35 hours on my projector I have had one drop out but I think that might have been me.Thanks again Joe. I will check whether my sony projector or Blu Ray player actual has options to change video output for DVDs to interlaced or progressive. Not a deal breaker either way as my main issue is/was this intermittant loss of picture problem, which still could be the 10metre HDMI cable. Luckily I have installed a second 10m HDMI cable in the ceiling, as well as 2 x cat 6 cables.
Have you made sure HDMI deep colour is turned off on everything?