Info from visit Cornwall:
Here’s the list of exemptions where you can still provide accommodation to people.
A person (providing visitor accommodation) may continue to carry on their business and keep any premises used in that business open…..
(a) to provide accommodation for any person, who…
(i) is unable to return to their main residence
(ii) uses that accommodation as their main residence
(iii) needs accommodation while moving house
(iv) needs accommodation to attend a funeral
(v) is isolating themselves from others as required by law
(vi) is an elite athlete, the coach of an elite athlete, or (in the case of an elite athlete who is a child), the parent of an elite athlete, and needs accommodation for the purposes of training or competition,
(b) to provide accommodation for any person who needs accommodation for the purposes of their work
(c) to provide accommodation for any child who requires accommodation for the purposes of education
(d) to provide accommodation for the purposes of a women’s refuge or a vulnerable person’s refuge
(e) to provide accommodation or support services for the homeless
(f) to provide accommodation for any person who was staying in that accommodation immediately before these Regulations came into force
(g) to host blood donation sessions
(h) for any purpose requested by the Secretary of State, or a local authority.
Note: (f) allows people to stay on in the accommodation if they were there before the lockdown came into force, so people don’t have to return home immediately.