Hello r1haz, I thought you might be removing the walls there.. Definitely don't block off the staircase... It is stylish and still practical... Just depends how you look at the idea of practical... It's actually more practical to do less and achieve more.!.. In the sense that I think you actually prefer the open plan idea...... It's less work as you're not adding to the work load with removal of downstairs walls....... Possibly increase the extraction element to the kitchen area and make sure the doors have good seals in the bedrooms... Nice looking stair treads can also work with the painted style which will really lend to the less solid feel. Open is preferable to dark and narrow, but you must do what you feel is the right thing... .... .. : ) )

I would loose the doors to the side- you won't enjoy the best view, don't need the light but could do with the wall space. I also think the double sided fireplace is a choice for you not future buyers as it limits the wall space and use of the side room (which is fine). Personally I don't think you gain much by making it a dining room next to your current dining space. But I do think reclaiming an underused room and it having lots of possible uses is a brilliant plan. I think when you get the builders in you should either put a porch on the side (and make it big enough to also be a laundry room). Alternatively make the whole room longer by extending a few feet into the back garden so that there is room for both a shower room and a laundry and then move the side door to the back giving more privacy to the bonus room at the front.

I had a bit of a panic about the same thing. I found out that it's ok if you just have a first floor, it becomes far more complicated if you have multiple floors. You should check yourself though.

opaque glass might work in this application.