Cutting DVB-T recordings is simple. If the recording is a MPEG2 transport stream (file ending .ts), you have to either convert or demux it.
If your just have MPEG2 Audio and Video, you can convert the transport stream to a MPEG2 program stream (PS, file ending .mpg) as described in this article and then cut it using TerraTec Cut!. That's it, you don't have to read any further.
If your recording contains AC3 audio streams you want to keep, you have to demux it to MPEG2 Video (.m2v), MPEG2 Audio (.mp2 or .mpa) and AC3 Audio (.ac3). See this article and then continue reading.

Open your video file(s) with Cuttermaran. Perhaps you have to open additional audio files if they are not automatically recognized. To use inter-frame cutting you have to configure a MPEG2-Encoder. I am using the free QuEnc, which you have to configure under Actions > Settings... > Encoding.
Navigate to the begin of the film and use the I-, P- and B-Controls to finetune. Click cut in. Navigate to the end, finetune and click cut out and then + to add the range to the cut list.
When done, click Cut audio and video to open the output dialogue. Specify the output path and change to the Mux tab. Choose any muxer you want and select the desired format. MPG or "Generic MPEG2" creates a standard MPEG2 file to play on your computer. Or create a DVD/VOB which you can directly burn, author or shrink. Start the process with Cut & Close.