Aha!
The wonder of pprune!
Under questioning, my chum informs me (in vague terms) er the problems might have started around the time I got Sky HD installed...
Gie me your bank details I say, so I can tie it in with the tech log error details. He doesn't have another Sky feed, but I guess the HD box has it built in?
Mr Vin, plse PM me the details of the 1-4 channel swap you managed, and I'll have a very happy bunny (and owe you a beer!)
Cheers
Mike
Thanks to all for the help