Sony Bravia KDL-V40A12U not storing channels since switchover and retune.

I have turned the power off completely over night do a cold start made no difference.

I have left the tv on after retune with the new channels for an hour, when the tv is turned off channels missing.

Channels are still there if I turn back on withing 5 minutes, obviously a memory problem...?

Anybody have any ideas how to resolve this issue.