How do I protect myself, and those around me?

It's basic, and simple. Be AWARE of the possibility. That means having a basic knowledge of how CO is produced, and how it gets into people.
Be ALERT to the presence of the gas - it practice this means splashing out £30-£40 on a domestic CO alarm - or even two.
Do NOT think that if your gas fire is burning with a nice blue flame, and not leaving any soot marks, that everything is OK. While it is certainly true that poorly-vented gas-burning appliances will produce soot and a yellow flame, by the time this is noticeable, there will be a LOT of CO around.
If you think that you or your family are in a contaminated building, get out, and do not return until you are sure it is safe. You should not use any suspect appliances until they have been inspected by a qualified engineer.