Location is brilliant, very close to central London attractions, about 15-30 mins by underground.
It was warm enough when we stayed on a cold days in November.
The studio had all basic equipment like kettle, toaster, microwave, little fridge with freezer, cooker(we could not make oven to work though), pans, plates etc.
Linen was fresh, bed comfortable. Sofa bed was hard, but it was ok for kids. There was a TV on the wall which had multiple channels. Also, there was a hairdrier.
The only criticism is a moldy smell of the building but I couldn't see any mold inside the studio though. I would say that photos show it a bit more beautiful than reality.
In conclusion, If you are on a budget and not too fussy it is a great option!