Time to get on the phone, that sort of behaviour from the STB is not good and if you delay getting an engineer sent out you will be watching very little telly over xmas
There have been posts made on forums with the SNR levels etc in them but I'm sure someone can post the relevant info again and then it can be added to the articles list
There is some mention on Robins site here
http://homepage.ntlworld.com/robin.d....html#pacediag
and here
http://homepage.ntlworld.com/robin.d...ps/signal.html
also there is information here
external forum link
but the CS/ TS people that pop in will be able to give you a more definate answer.