Hi
Well, problems did arise. After doing the scan as you said, when finished and back to live TV, I was getting a cycle of good normal picture/sound for about 30 seconds or so up to a couple of minutes, followed by a black screen with only "EC/PVR" in top left corner - this for about 20 or 30 seconds or so and then back to live TV - continuously, with only the time spans varying.
I then performed an Autoscan as that was what I did first time around, but unfortunately, that too displayed the same cycle of blank/live TV. I am about to revert to the original Terrestrial.xml
In fact, as I was typing this, it is in black screen mode with no response from the remote at all - now for about 10 minutes - I will need to do a switch off I think.