I've had the Humax DTR 2100 youview box from BT for a few days.
I cannot get the Red Button Services. When pressing the red button on SD or HD BBC channels nothing happens.
I turned on the youview box and Sony TV tonight. Sound and picture was O.K. I tried to play a recording from last night, picture was O.K., but no sound. Stop playback and return to BBC1, - no sound. Change channels, still no sound. Using the TV remote, select internal TV tuner, then reselect the youview box over the HDMI connection. Sound now works. Re-negotiation of the HDMI connection with the TV fixed the sound fault. Faulty box? or anybody else found this? Sound output from SCART lead was good at all times. TV is Sony 40 inch LCD V4000 series.

I suffer with the red button issue too. Firstly there is no red button services on HD so you have to go the the SD channels, but for some reason MHEG stops working all together on my box. I.e. it doesn't display on radio channels, off air channels etc.

The only way i have found is to switch the box off using the rocker switch on the back, or performing a soft reset by pressing the power button on the box itself for 10 seconds.

I haven't experienced any sound issues, but i have the box linked to my surround sound , and don't get sound through HDMI.

Hope this helps.

Mike

+1 for the red button bug.