On a domestic property, you can have a change in level up to 600mm tall without a guard rail. If, for some reason you are not a big fan of guard rails – maybe you are, who knows? For this basement scheme the external level at the moment is quite a bit higher than the proposed basement level, so I would like to bring the doors up off the floor so that we don’t have such a deep external well to get out of (or fall into, walk around) when we step outside. So, how about a bench seat that leads up to the doors, with a step? A normal bench is 450 high, but I only want  o n e  step and a domestic step can’t be higher than 220, so we can rise 440 with  two risers. A tread needs to be a bit longer than the rise, make it 240 so for two treads we have 480. A little deep for a seat so here’s some cushions in my through-the-wall-and-ceiling perspective.