For a comprehensive list of what you can and can’t do in a Tier 3 area please visit this HMG web-page –

https://www.gov.uk/guidance/tier-3-very-high-alert?utm_source=33e6265d-39c7-4edb-885f-ae360b405e35&utm_medium=email&utm_campaign=govuk-notifications&utm_content=daily