Iam in the US and I had a problem with ATSC(which is fixed), if you are in the UK can go into C:\Documents and Settings\All Users\Application Data\Microsoft\eHome\EPG (the folder will be hidden so you have to show hidden file) there sould be XML files in that folder three(there in the US).
Open the XML file and copy and paste and post them here, there may be be way to lock channels in there, post them and the names of the folders in the in EPG folder.
Richard Miller MCE MVP