We booked Mark'house after reading good comments, and really we are not dispointed. We stayed 2 nights at the house and there are 5 of us.
Mark wellcomed us himself, showed us the house and some tips about the place.
He was very flexible about checking in/out time. He let us check in early and check out late (our return flight was in the evening).
The house is a typically sevillan old house that has been very well renovated. It is very clean, simply but nicely decorated and comfortable. Having breakfast at the terrace was really nice. We didn't cook in the house (the food is delicious in tapas bars at Sevilla) but the kitchen is fully equiped.
The house is in a dead-end small street, so it is very quite here, we slept very well. It is also right in the old city (only 5mn walk from Casa de pilatos), so it's a very convenient place to visit Sevilla. There are some nice pubs and many shops in the big street close to the house.
Thank you Mark!