Nice small flat few meters from Kensington Gardens/Hyde Park, metro station(s), next to street full of restaurants and shops. The best location! The street is beautiful, clean and we felt good and safe.
On Friday nights, the street can be quite noisy (we had very warm weather and people were partying literally outside our window almost till morning), so you may need to get used to it at first. The other nights were fine. It also seems that the trash place (next to your door) is being emptied on Monday morning, so don't be afraid if you hear a stranger outside collecting the trashes veeery early on Monday morning (was it like 4am?).
We arrived at midnight on Friday (Luton) and arranged a taxi to flat (67 GBP in our case), but I have chosen this flat also because it is accessible by night metro. The keys are available at 24-hours reception across the street, so it is extremely convenient to check-in and check-out.
Flat itself is quite small, but will comfortably accommodate 2-3 people and it is furnished with everything needed. The linen and towels were clean, bed (and even the sofa) comfortable, enough amount of warm water in shower,.. all fine.
We would happily come back and recommend it to friends and family. Actually, when travelling to London again, this will definitely be the first place to check.