I guess the 1st thing to say has to be location, this place is perfectly located literally just in front of Hyde Park and Lancaster Gate Underground station. In other words, you can easily enjoy walks/run in one of the most beautiful parks and you are right in the center of London or can easily access anywhere with the Central Line.
The flat itself is a top floor (4th) and when we were there, the elevator was broken, so I must admit that a 4th floor with no elevator, was a bit challenging at the end of a day walking around the city and with a baby. Once the elevator is fixed, of course, problem solved. Personally, we lived in London for nearly a decade, and this flat is of very very high standards for what one would normally find in London. Is a bit worn out here and there, but nothing major or nothing that was a major inconvenient for us. In fact, it is really cozy, fully equipped, full of light and very spacious (again, way above the average in London). Everything was clean, tidy, and all details were taken care off.
Overall, we had a fantastic time in London, we consider this flat of very high standards, perfectly located and highly recommended. If we go back to London to visit, we would try to stay there again :)