The apartment is right in the middle of city. 1 minute from your Tube stop, less than 8 minutes on foot to Trafalgar Square, to the British Museum, to St. Martin-in-the-Fields, to the West End, to Carnaby Street pedestrian area, to Oxford Street shopping, to Covent Garden.
It is small. Was a tight fit for our family, which consisted of my wife, my 17-year-old son, and myself. But it was clean and convenient, with a friendly host. London is one of the most expensive cities on the planet, and to be in the middle of some of the best parts at this price is definitely worth it. Good and fast Internet, too, if that's important to you.