Not sure if ‘steering assist’ is the correct title - but, my Superb used to follow the road and complain if I let go of the wheel - the whole business irritated me and I somehow turned it off, how I don’t know.

Messing with the settings yesterday I noticed all driver assist gizmos are switched ‘on’ but the semi ‘self steering’ is limited to wobbling the wheel and putting some resistance in the wheel if I try to cross a line without indicating.

Is there a sub-menu somewhere I’m missing?

Lane Assist / Lane Keep Assist. 

What car are you in?  In mine (2018 L&K) the top button on the right side of the steering wheel takes you directly to the driver assist systems. 
 

You can then easily select what to have on or off.

Thanks guys but there appeared to be something different in the latest models inasmuch as The only options I have are ‘Lane Assist’ off / on and ‘Steering Wheel Vibrate’ off / on - seemingly no further menu’s……….

It's a brilliant feature......particularly for motorway driving. When I got the car first it was an irritation but now I wouldn't be without it.