Oh I love the mystery of the door that won't open!! I would be at it with a hammer and pry bar. Can't wait to see what you find. If you draw up a scale picture of the bathroom, we may be able to help you reconfigure it. Right now it does have some fun character, but it is quirky so I see why you want to sort it out. Diane
Bethie, I would lean towards keeping the original configuration of the walls. Looks to me the cupboard was added when the 'modern tub was installed. They had to fill the space and it provided a convenient spot to add the taps and shower riser. I bet if you replaced the tub with original period style and relocated the sink to its original location you would find it works great. Kathleen, an airing closet, I have never heard of such a thing until now. I can see the (in my mind) chimney effect that would make that work in a taller building. Interesting idea.