There's at least three locations - the Aobadai one is the one pictured in that spoon-tamago link, it's pretty ramshackle and basically converted apartment space

There's at least three locations - the Aobadai one is the one pictured in that spoon-tamago link, it's pretty ramshackle and basically converted apartment space, but the other two look a bit more standard working-space. I'm pretty sure from the details in the story that she was at the Nagatacho GRID one.