What certificates will I need to open a Sandwich Shop in the UK?

Only the Council in the UK can issue a change of use from retail to food. Food needs of an A3 license. depend on the amount of other food outlets that are in the area. You will need a Food Hygiene and health and safety certificate and a knowledge of all laws of catering as HACAAP and COSH.

His preparation area

It has to be rules and must be inspected by the Environmental Health Officer. If it is a craft store that will cost thousands to install a kitchen regulations. There is little benefit in sandwich shops and supermarkets are selling so cheap. You will have to pay rent, utilities, insurance, etc. before getting a penny profit. you need to speak with an expert.