I spent a few nights here while I was working in Canary Wharf (and it really is just a 15 minute walk to Canada Square). David is the most welcoming and conscientious host, providing travel sized toiletries as well as coffee, breakfast foods, and a few cold drinks. The room is clean, comfortable, and minimalist, with a gorgeous view. The shower has good water pressure as well.
The only thing that should be mentioned is that it's a top floor flat, so it may not be the best for someone with mobility issues, but I had no issue climbing a few flights of stairs. I would definitely stay here again!