Mark's place is very well situated. Near to different transportation services, shops, malls, restaurants, etc. you can go everywhere just walking.
The place is very comfortable. I was doing home office and the internet is very fast (never had an issue) and the rest of the room is very big. Sometimes it could be a bit noisy because of the street works and mostly from the store right downstairs the flat but overall it's okay.
I would say that the most important thing about Mark's flat is that he is a great host. Mark is very nice and always very helpful. he will reply to you if you have any doubt immediately. It is a very good thing that he is always for his guests. Moreover it would be lovely for you to have a conversation once in a while with him.
I would definitely will be back to Mark's place if I am near London in Hammersmith.