Great place to stay. The location was amazing with killer views of Buckingham Palace Rd. The place is about 3 blocks or a 5 minute walk away from Buckingham palace itself. Maybe a 3 minute walk from a train station and from there you can get to the rest of the city. 50 minute commute to LHR, I'd recommend taking the Piccadilly Line cause its 3-5$ vs 25$ for the direct(which saves only 10 minutes).
One big issue is that the key pickup location was a 15 minute walk away. It took 15 minutes to walk to the key pickup location and then backtrack another 15 minutes to the airbnb and then walk up 3 flights of stairs. Had to spend the same 30 minutes at checkout. I would recommend getting an electric scooter for the key pickup/dropoff.