What few people know is that you can default back to the free EPG. From the Playlist window, click Channels, select the channels you want (shift-click to multiple-select) and in the EPG column, select DVB (the industry standard for DTT) instead of tvtv. Then control-click on the program guide and select Update DVB Guide from the pop-up menu. After a few minutes, the EPG will update and you'll have the channels on the free EPG.
This will work in the UK, and might work in other countries as well, but this depends on whether the DTT EPG uses the DVB standard and is offered for free.

