UK Standard Visitor Visa implications during travel restrictions as a result of COVID-19 outbreak?

My wife (a Kazakh national) is visiting in the UK on a Standard Visitor Visa, staying with my family. She arrived on Feb 1st. Her original intention was to stay for approximately 3 months, until April 30th, and stated as such on her application form. She had been to the UK twice already, and had always departed in line with her intentions as originally stated during her previous applications. Her current visa expires in July.

Due to the COVID-19 outbreak, Kazahkstan will institute a one-month travel ban from tonight, preventing flights into the country. I'm a little concerned about what should happen if the ban is extended beyond that.

I understand that the Home Office generally frowns upon visitors who stay longer than their stated intentions, even if they do not overstay their visa lengths. But if the Kazakh travel ban prevents her from travelling back to her country until a date beyond April 30th, might this cause a problem in her future visa applications? Or is it a reasonable excuse, and provided she explains the extended duration of her previous stay during the future application, might it be okay?

Edit: On that note, she applied for this UK visa from China (where we lived at the time). Obviously, returning to China at this point, while theoretically possible (though we'd have to apply for new Chinese visas; they expired in February, a fact that she readily disclosed in her application), is hardly desirable. This is a circumstance that we could hardly have predicted beforehand. Her Chinese visa was temporary and she acknowledged this fact during her application. Might the UK officials think "well, you couldn't fly to Kazakhstan, sure, but why not go back to China? After all, you applied from there" ? I must stress that she never stated during her application that she intended to go back to China; indeed our plan was always for her to fly to Kazakhstan around April 30th, the original envisaged date of departure. Am I overthinking this, and would the specific country that she'd go to after departing the UK be of no concern to them whatsoever?