UK family of 4 with 2 kids: aged 14 and 11.
11 Dec - 14 year old loses sense of smell and starts coughing. No-one else has any symptoms.
Has Covid test on 15 Dec
Positive on 16th.
14 year old confined to his room to keep the others safe.
Still no symptoms for the other 3.
So according to the rules: whole family should isolate for 10 days if anyone has Covid....
So does their 10 day starts on 11 Dec and therefore 21 Dec is their "Ok, you can go back to Tesco" day.
So far, so good.
BUT yesterday morning their 11 year old starts showing symptoms so Dad, Mum and 11 year old go get tested and 11 year old is positive today!
Parents both still clear.
Weird....because kids were supposed to be less susceptible right?

So now their isolation clock resets and they have to stay home until 31 Dec. And if wife gets it, another 10 day lockdown starts!
Fun times.