Protesters will always complain that police action is 'heavy-handed, but the simple fact is, citizens are required to obey the police - their opinion of the reason for the instruction is not the issue.
Regardless of whether the prote4stors disagreed with the safety assessment, they were asked to move, and required to do so.
The lady did not commit a crime by serving tea, but failure to obey a police officer can be an arrestable offence under the Public Order Act Section Five.