The flat is as shown in the pictures. It was clean and Lisett was kind enough to offer us the food in her fridge. Communication with her was good, despite the fact, that she was on holiday herself, during our stay in her flat.
It is situated within zone 2, so all the attractions aren't far away and the cost for public transport is affordable.
The downside to her not being around was that she couldn't come by to help us, when we had a problem with the key (it had a small cut) and couldn't get into the flat. However, she did call me back and tried to help from afar. It was late at night and not much could be done short of calling a locksmith, which would have cost Lisett a lot.
In the end, we had a lot of good luck and could solve the problem with the help of extremely nice strangers we had just met, who offered us their spare bedroom to stay the night. (At the couple who took us in for the night: thank you so so much!!!) The next morning we could get the key replaced for hardly any money and get into the flat. Lisett returned the cost for one night to us and we spent an awesome week in London after that.
I would recommend staying at Lisett's. (I guess it is extremely unlikely that the key shouldn't work for you, it's now brand new ;) )