Have you tried this:
First you need to delete all existing channels.Menu > Edit Channels > Edit Channel Lists > Password (0000) and delete all channels, note there is a Select All button. If you were on a TV channel before going into the menu then TV channels will be listed first, delete them all. Go to Group, select Radio and delete all the radio channels. Press Exit on the remote control and when invited save all the changes.
You will now get a message saying No channels are available……, press OK. You should now be taken to the Installation menu, chooseManual Search. Select the first UHF channel number obtained from the digitaluk web-site for Channel (actually the order doesn’t matter) and press Search. When the search completes, Save. Select the next UHF channel number for Channel and press Search.....Save. Then keep doing that until you have all of your channels back. Once you have them back then press the Exit button. That should get all of your channels back. If that doesn't resolve it try to retune it. Press the reset button for 8 seconds and see if everything comes back. keep me posted