Technosonic lost channels?

My freeview box just stopped working last week, now after retune I am missing BBC channels, rest of channels have jumped to 800s and are all scrambled though says good signal.

I have changed scart and aerial but still the same, checked and doesn't seem to have been any work at transmitter,

My details are:

Transmitter - Crystal Palace
set top box - Technosonic model - STB 2009
RF in and out
2 scart

Thanks,
Roy.

OB
April 2009