I would not recommend this place for any family with kids. First of all, it's not as close to public transportation as we hoped. Closest bus / underground stations are probably 5 minutes walk away - this may not be much, but after more than a week of traveling, it gets pretty tiring. Also, walking up tight 4 flights of stairs get pretty tiring after a few days (be aware of first floor neighbor who keeps complaining about noise coming from the stairs - we had to tiptoe our way up and down). It's not an ideal place which you can easily come back and take rest in between sightseeing.
We also had, I guess, fantasy about walking to Portobello market in the morning but it's not as close as I thought from looking at the map (London was much larger than I had imagined, in general). It was very close to Princess Diana memorial playground, which my kid liked a LOT.
That said, everything else about this listing is as described. All appliances and furnitures were new and very clean.
But if we were to come back to London, we'll probably opt for a hotel near an underground station, near the center of the city.