We had a really good time in Mark's apartment and, even though we didn't get to meet him, Mark was an amazing host! He was very responsive from the start and he sent very detailed information about the apartment and how to get there before our arrival. He regularly checked in with us on arrival day to make sure everything was going well.
The apartment is very nice, cosy and clean. Both the bed and the sofa bed are very comfortable. The apartment has all the necessary appliances and more (dishwasher and washing machine). The cherry on the cake is definitely the roof top! Given the time of the year (October) we didn't get to enjoy it that much but it must be amazing in the spring and summer.
Mark's place is very conveniently located on 2 tube lines. The apartment is in a quiet street lined with small buildings and houses.
I would definitely stay there again!