This is a lovely little house in a great location. We stayed as a family including two kids under the age of two years and it worked out very well as a place to stay with kids (note there are lots of stairs which may be a concern for some families). We were also surprised how quiet it was at night given the proximity to Portobello road. Noise was never a problem. This was possibly to do with staying in winter where the street buzz isn't as much as the summer and we could always keep the windows closed.
I had no real contact with the owner, Matthew. The property is being managed by an agency, which wasn't initially clear to me. But it worked out ok. In fact they were very accommodating with providing cots, a buggy and a high chair for the kids.
The only real negative point for us was that the kitchen was a bit uninviting. Some maintenance is needed to the kitchen units and the pans and utensils are general old and of low quality. Some items were also dirty when we arrived.
Overall I would definitely recommend this.