I've known this family for a long time now (6 years) and get on really well with them. Since they moved house about two years ago, I've been tutoring their two children in their open plan living room with the lesson at the dining table, while the Mum watches TV (usually the news, which is depressing...)
I've tried to be easygoing about it by asking to turn the volume down when it gets especially loud and when the children look either distracted or can't focus because of what's on the screen...but having spoken to a few people that I know I've realised that I should probably actually say something.
Last lesson their grandma was around from abroad (she's staying for a while and she mostly just watches TV on the couch) and she was watching a film with the Mum, which was violent and quite loud. I politely asked to turn the volume down, and so did their children, and the Mum would turn it down by 1 each time, which was really frustrating as it would make no difference.
I would have thought that, at the minimum, you would want to give your child a good environment to study in, and especially given that they want their kids to get good grades/sit the 11+ having the TV on every lesson cannot be conducive or setting a great example... I feel particularly awkward about asking now because the grandma is around and she probably doesn't have much to do. Or sometimes the Mum just plays YouTube Shorts on her iPad without earphones