As far as I see, no one has ITV HD working on DM800 yet. ITV HD is broadcast H.264 but inside an H.222 wrapper. Some HD boxes have recently had their software modified to enable this (H.222 codec added I assume) but not DM800 yet. Shame as it's a good FTA HD channel.
As for Sky EPG again I'm not aware of this on DM800. With Sky UK you can only see current & next program. A seperate Enigma 2 plug-in would be needed to find & display anything else. I think there may be an Enigma 1 plug-in in existance, but not yet Enigma 2