As noted in our comments, the location is Excellent and within walking distance to EVERYTHING (except maybe Tower of London). The location is on a very busy night life street (Thursday - Saturday), this adds to the noise level (flat #3 faces the street). However, good insulated windows make this livable, unless you like to sleep with the windows open, then it could be a serious problem for some. The street lights are just outside at the level of the flat, but there are good black out curtains to control the light.
The Washer/Dryer are in-flat and Coin Operated. A standard load will take 30 min to wash, and about 2 hours to dry in the condensation type dryer. This will end up costing about 6-9 pounds to do a standard load. There is no place or line (usually in a hotel shower) to hang your clothes to dry if you wanted to go that route.
Flat 3, at no fault of the owner, has very uneven and 'bouncy' floors. It's livable, and doesn't seem dangerous, just feels odd.
If you need a power adapter (for US or other EU countries) you should buy them from the street vendors.. Don't over pay, they'll ask for 10, offer 3, and you'll get it for 5 pounds. Otherwise be sure to bring an ENGLISH type plug adapter (hint, it's NOT the one with the two round plugs)
There's no lift in the building, so you'll have to be able to walk up the stairs if you choose a upper level flat.