Trying to resolve this problem on my sisters' exact model too! Was going to try telephoning Bush and/or Freeview for any help first. In the Instruction Manual (p36) under DVB Main Menu/Setup/Reset Receiver, it says that "all settings and channels in the memory will be deleted. When you want to return to the Manufacturers Settings, you may press green button after entering the PIN code in this menu. Your PIN code is 7139."
This code would therefore appear to relate to this model. Will need to get ok off sister to attempt this, in case lose all channels! Dare you try it?
Good Luck
Tony
Tony D, December 2009