Not sure why you are self-isolating unless one of you is displaying Covid symptoms. None of you have had direct close contact with the positive testing person .........
Government advice to the positive test person is ........
Tell people you've been in close contact with that you have symptoms
You may want to tell people you've been in close contact with in the past 48 hours that you might have coronavirus.
What does close contact mean?
They do not need to self-isolate unless they're contacted by the NHS Test and Trace service. But they should take extra care to follow
social distancing advice, including washing their hands often.
If they get any coronavirus symptoms, they must self-isolate and
get a coronavirus test as soon as possible.