These are classes of planning use under the Town and Country Planning (Use Classes) Order 1987, and are the lawful planning use that may be carried out at the property in question.
The classes are as follows:
* A1: a shop
* A2: professional and financial Services, (such as estate agency, bank)
* A3: restaurants and cafes
* A4: drinking establishment e.g. a pub or a bar
* A5: hot food takeaways
So you could not sell food from an A1 or A2 property.
But you could either:
a. rely on permitted development rights- some changes between classes are automatically OK; or
b. seek planning permission for change of use.