The FCO updated its global advisory against ‘all but essential’ travel, exempting destinations that no longer pose an unacceptably high risk for British travellers. See link below.
Update to travel exemptions list. Additional 19 countries and territories added: Laos, Cambodia, Fiji, Samoa, Sri Lanka, Cuba, Guadeloupe, St Barthelemy, St Martin, St Maarten, Aruba, New Caledonia, Curacao, Cook Islands, British Indian Ocean Territory, Falkland Islands, St Helena, Ascension Island and Tristan da Cuna
http://Coronavirus (COVID-19): countries and territories exempt from advice against ‘all but essential’ international travel: https://www.gov.uk/guidance/coronavirus-covid-19-countries-and-territories-exempt-from-advice-against-all-but-essential-international-travel?utm_source=47bcde03-f332-4474-9834-2976cecae768&utm_medium=email&utm_campaign=govuk-notifications&utm_content=daily