Update.
I received an email today from Humax regarding a firmware update.
Installation completed. I can now confirm that the original sound problem I was experiencing is cured.
Anyone else who experienced the same problem. Remember after the firmware upgrade. Go to settings. Audio & Video. Dolby Advanced Settings. Switch MS12 Transcoding off.
That’s it.
I have tried it to test.
Normal stereo transmitted tv stations now leave my home cinema receiver in Dolby Pro logic II. Yet when I play a film I have recorded on the harddrive that I know is in Dolby Digital 5.1
My receiver now automatically switches to mult- channel.