The positives: a wonderful host with great communication.
A great, central location, particularly if you love the theatre.
Only about a five minute walk to the tube and you have the option of a slightly longer walk to another station if that line suts you better.
The building is very safe, with a separate keyed entry to the common door at ground level.
The flat is very well equipped, with everything you could need for a short or a long stay.
Like a lot of holiday rentals there's a continuous cupboard with all sorts of herbs and spices and whatever long life food previous guests have left. Tip: don't shop until you check the cupboard.
The flat is tastefully decorated and includes a huge selection of books and good TV reception.
For an inner city flat, this is a good size with a large, modern bathroom. It's much larger than most London hotel rooms.
The main bedroom is comfortable and reasonably quiet. Like most inner city properties of this age you can expect to hear the neighbours from time to time and they can hear you. A bit of common courtesy goes a long way or you can just bang on the wall. We were woken by upstairs neighbours a couple of times in the wee small hours but you get the same in most hotels.
The plant covered balcony is gorgeous. It's small but at the end of the row so there's plenty of room for two people to sit and enjoy the sun.

The negatives: the front room can get noisy as you can hear people outside the pub across the road, and the proximity to the main road means there are sirens all night. The fold out bed is not comfortable enough for a long stay and I wouldn't recommend using the living room as a bedroom, unless you are a heavy sleeper. This is not as much of a problem with the main bedroom but in general terms, if you are sensitive to noise look elsewhere.
There were some maintenance issues we raised with the host, including the need to upgrade the bedding in both rooms. His response has been sincere and we are sure that these things will be rectified soon. Mostly they are minor issues relating to the sort of wear and tear you get in a holiday rental.

The final word: I would stay here again with my husband or on my own provided the maintenance issues had been addressed.