Maria's accomodation is very close to the Plaza de Espana and within walking distance of a lot of the historical buildings and places of interest. The house itself is very beautiful and very well maintained. Maria is the sweetest host ever. Overall we can't think of a better place to stay in Seville.
Pro-tip: Be sure to wander around the parks close to Maria's place. Especially in Andalusia's heat it is nice to find shade, lovely fountains and the coolest trees there.