It may have been the wean's mother - overly aggressive cleaning and accidentally setting the automatic delayed timer.
When this happens on my oven this is what I do...
Switch off and on again so that the clock flashes
Depress and hold in buttons 2 & 3 from the left
Set the time (any time will do) using the plus and minus buttons.
Now you're cooking on gas - or electricity...
Good Luck..., October 2016