I would leave. I would have someone trusted from my side come to be present whilst the inspection was taking place (your mum, sister, bff?)
I wouldn't want to stay and present an opportunity for confrontation. I wouldn't want her to know that she was providing a disturbance in my life. I wouldn't want to potentially create fuel for a family drama.
But, I wouldn't want her to have free rein on my house, either.
What a sucky situation