There are legal restrictions on tortoises:
However the tortoises you find in this country are usually Horsefields, which are class B. They are sold without any certificates required. It is extremely rare these days to see other tortoises than Horsefields and the people who have the rare ones tend to know licences are needed.
Therefore you only need to worry about posts involving tortoises if there is particular reason to think it is an unusual one.