Triggers are based on an event, which can be a time, state change / sensor value change, that kind of thing. Can you say more precisely what your trigger should be? Leaving the house? At a particular time, only if you're not home? Something else?

You can use the NOT condition, but you can't NOT a trigger as far as I know.

If you've got presence detection set up, e.g. "device_tracker", then you already have access to a state called "not_home". And if you have that device linked to your "person" entity, then it will say whether you are "home" or "not_home"

Some of my light bulbs turn on after a power cut because they do not have a Start-Up Behaviour that I can set, so, if  a light turns from Off to On and my location is Not Home then send me a notification so I can turn the light off.

That one should be pretty easy. Trigger on light status changing to On, condition of location is "not home", send a notification. I don't have people / location set up so I can't easily write an example automation.

Ah, I was doing that wrong, now I can see if I am home or away, thanks.

Thanks for the replies. I now have an automation that detects light turning on and will turn them off if I am away. My Hue bulbs let me set a power-on state but the other brands do not.

If anyone knows of any other brands of zigbee bulbs that have this option I would be most interested.