A few weeks ago we found that Freeview channels 3, 4, 8, 9 and 11 were programed but kept cutting out. Other channels have been working fine. 

Today I rescanned both by channel and frequency, all channels except those owned by Mediaworks, work fine. 

I am aware that MediaWorks had outages earlier this year but these issues have been over the last month. Currently the MediaWork channels are not programed in the tv as scans can not find them.