This situation is different. They say she's theoretically safe for twelve months. I reckon she's safe until 29/3/19. After that it depends on whether we have left or not. If we have left the EU by then, whoever replaces her will not be to blame directly for the result. They will start with a clean sheet. It will be relatively safe to replace her.

If we have not left, the situation is more fluid and more difficult to predict. Her replacement will then be responsible for leaving or not leaving. That would be a much more vulnerable position.