Our family of four had a nice stay in Helena's apartment. It was located very close to the Castle, as described, and has a spectacular city view out the kitchen and dining room windows and from the small balcony accessed via the living room (you could stare at that view for hours!) There is another balcony in one of the bedrooms (not in the master bedroom with the ensuite bathroom, but in the other bedroom with the double bed). Be aware that balconies in Lisbon are quite small--there's room for one or maybe two people to stand or sit on a small chair (in our observation, this is not unique to Helena's apartment; it's common throughout Lisbon.)
Helena met us at the apartment and provided some helpful nearby recommendations for lunch and answered questions we had throughout our stay. We have shared with her some maintenance issues that require some attention (e.g. the ensuite shower does not drain adequately and we experienced some minor challenges with the hot water heater). I would anticipate these issues will be resolved promptly.
For planning purposes, some travelers might want to know that the wifi did not reach into the bedroom areas during our stay, and we were unable to access sporting channels on the television (we are US Open fans, and wanted to catch match highlights at the end of our sight-seeing days)--we packed our Fire Stick with us, and were able to gain access that way.
The apartment worked very well for our needs and we would recommend to others.