My Digibox (Grundig) is about 3 years old. All of a sudden all of the BBC/ITV channels appear as "broken up", whilst all other channels have a perfect picture (although there is a buzzing noise through TV speakers when volume is turned up). The Sky Customer Help guy, ran through various adjustments - none of which rectified the problem. I was told that I need to call out a Sky engineer at £65. Anybody had a similar problem? Pal.