Marta's Place is very well located for a trip to London - we bought an Oyster card - the walk to Hammersmith station takes about 10 - 15 mins. The modern apartment is very nicely furnished and super clean! The area is fairly quiet and we had no trouble with noise inside. Marta herself is very helpful and promptly answered our queries before we arrived
Our only reservations are the staircases - we can manage 3 flights of stairs but they are narrow which makes lugging large cases up and downstairs somewhat difficult. Plus the parking space (which is a great bonus if you have to drive) is only suitable for smaller cars as the entrance is also narrow, and the car has to be reversed out, past low stanchions on one side.
However we can recommend Marta's place for a reasonably priced stay in London.