There are the BBC/Itv/Sky interactive channels which are normally only available via the red button.
These are flagged as data streams when you scan them in and wont show up on the dreambox but can easily be viewed by doing the following.
Use DreamboxEdit for this get it HERE
Import your channel list into it, find the data streams listed below, right click on each of them and convert them to tv channels.
Reload the channels back onto the dreambox & away you go.
Services: ITVi Quad,stream2,stream44 - ITV Interactive channels
Services: 1381-1399 - Sky Sports Interactive Channels
Services: stream 0 - 6 - BBC Interactive Channels
There are others showing but appear to be only feeds of channels that can be viewed normally.
Best Regards
Ten Below