That is for them to work out if they want to stay open. All the Cafes I have seen today were all complying with the rules and it would appear that KFC are doing all they can.
Supermarkets have had lines 2 meters apart since day dot. If a business type or individual store cannot do the same, I can;'t see an excuse. . If I was managing a store, I'd have signs up (even though after weeks of supermarket activity should be no need) and the signs say please keep 2 metres apart, otherwise no service. Yes, that is pandering to the lowest common denominator, but so be it.