Key is no longer PM. He has retired. He is a backbencher. The reason he retired was to have more time with his family and he should be able to do that without the Herald paying a photographer to take long distance photos of him and Bronagh at a swimming pool, having lunch, filling up a car with petrol etc.
The Herald may claim they did not commission the photos but were offered them, but there is no doubt they would have paid for them, and paparazzi only take photos of people when they think someone will pay for them.
Key was fair go (to a degree) when he was Prime Minister. He and Bronagh should now be left alone on his holidays. The Herald should respect his right to a private life and not run any such photos in future.