New Freeview Channels Disappearing

[Ed Strong]

When I re-scan my TV (Goodmans, 18 months old) for the updated Freeview channels 27, 33 and 46 (ITV1+1, ITV2+1 and Challenger) they all show and picture quality is excellent, as is the rest of the channels. However, after the TV has been switched off, once I switch on again these channels disappear and Channel 20 is still showing. Do I have to re-scan every time? I've not had a problem before. Any ideas?

[silka]

Don't think so.
When I do mine they stay.