First of all, Mary is an absolute dream! She has a sweet kitty cat who lives with her and she herself couldn't be more welcoming or accommodating. I was there for a wedding and had to fly in and out in just a few days. Mary made sure I had everything I needed and then some. She's definitely a problem solver and tries to make everyone's stay fantastic.
The set up is great, so that even though you are sharing her flat, you have a key and as long as you are quiet when you come in, it's not very intrusive to others. Not a private entrance, but almost. I would definitely stay here again. NOTE: It's very near Islington Town Hall (4 minute walk, I think?), where a lot of weddings happen. The location was very convenient to get to my friend's wedding there.