Expanding on the OP slightly, I would be more adventurous. Since the A levels season is upon us (whether the exams are sat or not). Year 13 will not be in school/college now anyway. I would, therefore, certainly allow 6th form colleges to open, since they will only have the Year 12 students in college and "double" the space available to safe distance.
Likewise any small business (hairdresser/nail salons/barbers etc.) that can work safely with social distancing, and the use PPE, should be allowed to open. My chiropodist is still open, she obviously can't keep 2m away, but does wear a mask and face shield.
This virus is going nowhere soon, even if we can manufacture a vaccine, people need to start "living with it", the more people out and about (2m apart when they can be), the more "herd immunity" will be acquired.
Hospitals etc. are learning on the job how best to manage/treat Covid 19, on a daily basis. Certainly the use of ventilators is being re-thought, other (less invasive)methods of getting oxygen into the lungs are being trialed by some hospitals, by using equipment re-purposed for other conditions (sleep apnea). Drugs normally used in the treatment of Ebola, have also had some success in managing this disease.
I realise I will probably get shot down by some on here, but we can't hide from it forever (in the hope of a safe, reliable vaccine being discovered), we need to start living with it (and the unfortunate outcome, for some, if they do catch it) on a day to day basis.
As i stated on another thread I am a key worker, and have been in work throughout the lockdown, I certainly don't feel afraid or frightened by being possibly more exposed to Covid 19, because I haven't been able to stay in doors.