clearly if you have adults who are unable to look after a small child, that is an exceptional circumstance
Except this point was not reached.
Many, many people with caring responsibilities were self isolating because of symptoms at the end of March. They did not all pre-emptively jump in a car and drive 250 miles, because the government advice was very clearly 'stay at home'.
If the government advice had been 'stay at home, unless you would rather move somewhere else', that should have been made clear to everyone, and Dr Harries could have said this on 24th March. I am sure that many people self isolating alone would also have liked to move to another household, incase they needed support, but we were told to stay at home.