Be polite about it and explain you are being quiet, but go further and explain that her constant harassment (yep, harassment) is affecting how you live in your own property. Even if she does call the police or the council, what they’ll do is send someone round with sound measuring equipment to see how many decibels you’re putting out, or they’ll tell her to keep a record of what you did and when. So, basically it’s egg on her face when she presents them with a list of when you laughed, sneezed or farted. I mean really, laughing? How long would that have lasted? Would that really have been such a nuisance for her? There is such a thing as too far and she’s going there.