A hot food take away use relates to the sale of hot food for consumption off the premises. Until 1 September 2020 this use was classified as Class A5. The Business and Planning Act 2020 introduced changes to the Use Classes Order. Former A5 hot food take aways are 'sui generis' which means they do not belong to any use class and do not benefit from any permitted development rights.
The full regulations can be accessed here: https://www.legislation.gov.uk/uksi/2020/757/made