This place was amazing location wise, and it's clear the owners have invested a lot in the decorations and theme. There were even some thoughtful touches such as a power converter available, and a very comprehensive guidebook.
However during our stay, the pull out bed was broken, so one of us slept on the floor, which was dreadfully uncomfortable. The couch has also seen better days and needs careful cushion placement to be sit-able. The windows were also leaky and letting in drafts that were strong enough to move the curtains - therefore it was also just slightly warmer and quieter than the street. We also weren't allowed to leave our baggage for a half hour before check-in, which was surprising given how close to check in time we wanted to store them. No explanation was given for this choice.
The final critique is something that isn't under the owner's control but I think should be known for future guests. The hallway up to the flat smelled horribly - like cigarettes and waste. The smell crept into the foyer and bathroom so we had to carefully close the door to avoid ourselves and our belongings smelling the same. Finally, if you have more than one person, please know it will feel extremely small unless you're planning on sharing everything.
There was obviously a lot of attention to detail in the decoration, I can see how Harry Potter fans would be enchanted! The location was also very convenient to the town center, Edinburgh castle, etc. I just wish some of the time, cost, and energy spent on the decorations could have been spent on foundational necessities like a sleepable pullout bed, sit-able couch, and windows that block the wind.