How can I unlock the child lock on a Bush 6694 tv without the remote?

We put the child lock on our Bush 6694 tv using the remote control. All was well until our 20 month old son decided the remote needed a wash and promptly dropped in a sink full of water. Remote has been dried out and battery changed but does not work. Problem is we can switch the on off button on to put the tv in standby, but because the child lock is on we can't then select a channel, use the menu button or adjust the volume from the buttons on thr front of the tv. Any suggestions on unlocking the child lock without the use of the remote?