Perform randomised testing of both current cases and antibodies at various locations around the country to ascertain the true spread of the virus so far.
Ensure a full supply of PPE. Also ensure a supply of masks for the general public (though possibly a little larger than the Abenomasks).
Perform a number of tests around the country in areas that had low and like for like amounts of cases. In these areas, I would have some returning different year groups to school, some permitting young adults in single households to return to work, etc.
Ensure that these areas had tip top testing and tracing.
Clearly inform the public that all these tests were going on, and that based on the results of these, and further tests in the future, other areas would be released in the same way.
Examine the results in 3 weeks time and expand the areas with loosened restrictions that did not result in a rise in infections.
Use the Nightingale hospitals as elderly discharge centres, rather than releasing patients to care homes. Test all residents of care homes and transfer any positive cases to the Nightingale hospitals (very sad, but the only solution I can see at this point). Test all care workers. Do this immediately.