Hi Nigel.
Hope you had a chance to get your Tv fixed. The next time something like this happens, take the following steps.
1. Obtain a original TTV 2926 remote. Universal remotes will most likely convince you to commit cuicide.
2. Turn the set on.
3. Press and Hold the "Display" button on the remote for approx 5 - 10 seconds.
4. The "Child Lock" should now be disabled :-)
Johan at Westech Bloemfontein 079 873 5427, May 2011