I don't know if this is a problem with my 1800T or with DTT or with how I have things set up, so perhaps someone could advise....
The 1800T is output to the TV (Sony Bravia) via HDMI cable. The TV is set not to use the internal speakers and audio output is via a phono cable to my Orbitsound soundbar. On most channels I can control the volume via the 1800T remote control. However, when switching to certain channels, the volume shoots up to a painful level and the 1800T remote has no effect on volume level. (Although the sound can still be muted). I have to use the Orbitsound remote to reduce the volume level significantly. Then when changing channels back to a "normal" channel, the sound is almost inaudible until I use the Orbitsound remote to increase the volume again. For example, all the channels from 1 up to 44 work using the Humax remote, but channel 45 (Film4 + 1) has the "very loud" problem and so do a handful of others. I am on the Winter Hill transmitter, I think.