A wonderful flat, in a perfect location. Heathrow Express train from the airport to Paddington, and the flat is but a brief, easy walk away. Another couple of blocks landed us in Kensington Gardens, which we used to walk to the V&A, and science museum. The shared hallway in the building is a bit worn but the flat was clean, well equipped, comfortable, and surprisingly quiet.
Mathilde made special arrangements for us to get our keys as our flight came in after the shop, where the keys are usually picked up, was closed. And she was incredibly responsive about getting us settled in, though it was fairly late.