Hey team

Having an issue with MySky HDi where the signal on the HDMI port is intermittently dropping out, and seems to actually cause the box to "reset". 

I have just had a box swap done last week, as the previous box was "freezing all the time" - ie the picture would freeze, and I had to do a physical box reset using the magic red button.

So the issue of HDMI dropout is happening on the new box. I am pretty certain it is just an HDMI issue, as I also have a RF Modulator to send signals via coax to other TV's and is I set the main TV on the RF feed, it will go for hours on end, and not drop out.  But set the TV on HDMI input, and the box drops out after random time periods, and will come back to life a few minutes later (it shows the "please wait, updating listings" message when the feed comes back).  The annoying things is every drop out will cause any programme that is being recorded to fail...

The only other factor to take into account is the Sky box sits in a media cupboard, and the HDMI signal is sent to the "main TV" via a HDMI sender (over 2 CAT-5 cables).  I have had this setup running for over a year now with no drop out issues. It only seems to be occurring on the new box (versus the last box which suddenly started freezing)

So, do you think I have been given a dud box, and should just get on the blower for another swap?
Or is there something else going on?
Anyone experienced issues like this before?