Can you confirm what happens when you press and hold the lock symbol for over 8 seconds?
Model Number T13D82N1
Model Number T13D82N1 - Thanks
The child lock is activated to deactivated it you need to press and hold the button which controls the dual circuit hotplate. Its the picture of a circle inside a circle. Its the left hand side one.
Press and hold that for several seconds and it should take the child lock off.
Let me know how it goes.
I've tried your suggestion but nothing has happened. Don't worry anymore about it, I have arranged for an engineer from Neff to come. Thanks for trying