Even if this house is legal I would suggest that you think through your escape from it in the event of a fire. You may need to have a portable fire escape ladder to enable you to exit an upstairs window should the front door or stairs be blocked by a fire. It is important to remember that in the event of a fire most people panic, if you have not thought of how you are going to get out beforehand your panic may get the better of you.
I would also suggest that you make sure the house has adequate smoke alarms and extinguishers installed. If you are not sure what you need or how you should best exit your house in the event of a fire, you can ask your local fire brigade to give you some advice. They will make a free home visit usually.