We cannot say enough good things about Mark's apartment. I'll summarize the different aspects below:
Location: Great location in Chelsea with a major street that has all of your immediate needs like groceries, shops, restaurants, cafes, etc. It's also great for hopping onto a taxi if needed. Harrod's is also about a 10-15 minute walk away.
Apartment: The apartment looks just like the pictures if not better. It was hotel-level clean and felt cozy while still having plenty of room. Mark leaves detailed instructions on everything you might need (washer/dryer, how to work the stove, how to work the TV, etc.). It is fully furnished and supplied with everything you will need (shampoo, conditioner, soap, dishwashing soap, sponges, full kitchen supplies, etc.). Mark has thought of everything.
Communication: Mark regularly responded within minutes whenever we messaged him.
Arrival: Mark's instructions were very clear and getting into the apartment was quite easy.
Thoughtfulness: This is more of an intangible. Mark really has thought of everything. He left us some things to make cocktails if we wanted to (sparkling water, sparkling rose lemonade, a lemon). And either for tea or for our daughter, he also left a small milk in the fridge. There were electrical plug adapters, London guides, and a three page list of recommended restaurants. He also had laundry detergent and spare umbrellas if we needed them. Lastly, it really felt like we were his guests. There is a lot of art in his place and you feel like you are staying with a friend.
I really cannot recommend this apartment enough. Whenever we return to London, we plan to stay here. Thanks Mark!