[ALL] Technicolor Modem - can't manually select Channels 7 to 11

On 2.4 Ghz, Channels 7 to 11 greyed out and no option to select even when changing the mode eg. 802.11 g/n and 802.11n. Also, changing the Channel Bandwidth toggline 20 or 20/40 doesn't help. This would not normally be an issue but I'm in a very congested area and the better channels (using a network app) for whatever reason seem to be greyed out on with modem. Is there a way to fix?