[mythtv-users] Duplicate Channels found since Digital Switch Over and some don't work !

[Paul]

I'm based in Northumberland, and since the local 'digital switch-over' 
I've retuned my Mythtv backend several times, and I keep getting 
multiple channels for the same channel, and some of these aren't 
watchable (they never lock).  For instance I currently have two ITV2 
channels, one with Freqid 29 that doesn't lock, and one with freqid 54 
that does.

Is there a reason these duplicates are being generated, and is there a 
way to either stop or hide the non-working channels automatically 
without checking each channel ???

Thanks

Paul.