So what would be your suggestion of what she should do then? This is why this entire isolation thing is bullshit at the moment. Her parents are most definitely doubled vaxxed by now and Grace will have had 1 if not both doses. Her parents are teachers and can't take time off just to isolate to make it easier to follow the rules. Entire families can't all isolate when one person gets infected or society will turn to tit. Realistically, we don't need to be taking isolation as seriously as we did before the vaccine - just reducing as much contact as necessary during that time.
It’s again the thing where Grace herself makes a thing of something that doesn’t need to be a thing.
If she’d just been in her house as normal, even spending most time in her room without the “I’m confined to my bedroom” chat, I don’t think anyone would have commented on it. It’s the way she says one thing then is shown doing another. (See the door being wide open, banksy in and out.) The same with her and Honour keeping distance but not, the dairy allergy that was a focus then suddenly eating dairy etc, there’s a real pattern of it with Grace.
Her parents do still currently legally have to self isolate, so if schools were open they’d be off work but I still don’t see the point of her isolating from them within her own house when she’s tested positive and has been around them.
If she was a close contact of someone and was isolating for that reason, it would make more sense to me to isolate herself within the house as far as possible.