Barbara's husband Martin greeted us at the apartment as planned and had lots of helpful advice for us at the start of our trip. The apartment was exactly as advertised and for just two of us was a good base for exploring Vienna. The apartment is within walking distance of the palace and the zoo and it is possible to walk to the centre of Vienna, though it is easier to walk to the nearby metro station and head in from there. For good quality, fresh, affordable pizza we can recommend the local restaurant Disco Volante which is about a 15 min walk from the apartment.
Barbara was very prompt at responding to my messages and helped us arrange a taxi back to the airport.
All in all a very pleasant experience.