This reminds me of my first flat. Classic Victorian house interior with an original fireplace, books in the alcove. However I wasn't stylish enough to have those wonderfully chic grey walls with high white accents.
Small Space, No Closet! faux-built in idea. Using a small bookshelf turned outward and a curtain, why not create a closet in a nook or behind a door? Making sure to anchor the bookcase to the wall for stability