A while back I posted about getting a working MHEG EPG for mythtv. Didn't find what I needed so I wrote one. It's a single script that only requires bash, awk, sed, and rb-download.
You need rb-download, http://redbutton.sourceforge.net/ and then the script. It currently converts MHEG-5 DVB-T to XMLTV xml file. Right now I get a 7 day listing using DVB-T MHEG-5 data. Listings include: title, description, freeview rating, teletext, HD quality flags, and start/stop times.
Feedback welcome, so please email me comments/problems.