Ian's listing is incredibly accurate: the flat is centrally located next to Trafalgar Square and most other visitor destinations and just a stone's throw from two tube stations. You can walk to most of the main attractions! There's also a few grocery stores in the same block. The flat itself is clean, bright and welcoming. Having a clothes washing machine was quite helpful at the mid-point of my trip. The bedroom is quite comfortable. On exceptionally sunny days, it can be bright in the morning (there are white privacy blinds), which is great for an early-riser like me, but as a few other commenters have noted, if you plan to sleep in very late and are more sensitive to light, you may consider bringing a sleep mask. I imagine that for most folks, you won't need a mask (I slept in a few mornings and had no trouble). And it's best to get up and enjoy the London sun anyway!

Ian was easily available for questions and very helpful. I hope to come back to his flat the next time I'm in London.