We were there for a conference at Allianz Park and its absolutely perfect to get there (direct bus, 10min.). But also using the train to get to the city of London is very easy (app £3, 25min).
Edan is a great host, always quickley responsing to messages and he also had good tips for us for getting around.
Flat for two people was luxus, and both, bed and sofa were very comfortable. Flat is also big enought for 4 people in my opinion. The flat is perfectly(!!) equiped, clean and warm (heating can be adjusted by yourselfe!!). You have everything you need also for longer stays or when in need of washing or so.
The bedroom it is absolutely silent, the sofabed is quiet during the evening/night but you can slightly hear morning traffic starting around 7am; I have light sleep, so I used earplugs but if you have a good sleep you might even not notice it.
We would definitely recommend this place!