While it is good that spouses of national leaders spend time doing good work and supporting charitable causes, I wonder if such activities can be considered as "official visits" as made out by this newspaper.
If I am not mistaken, there is no official position as the spouse of the Prime Minister and the person holds no authorised brief in the system.
Of course as the wife, she commands authority by association and may even represent him for certain unofficial functions. For instance, it would not be the proper protocol for her to welcome another head of state on an official visit if the Prime Minister were sick.
Maybe the NST should elaborate why they deemed this an official visit?