that's a lot of blah blah criticism of policng tactics by the Met-they handled it excellently, as you correctly say 'there was little violence' and little damage and certainly not dozens of officers taken to hospital by ambulances that are needed elsewhere.
Southport was an example of the police being unprepared for the sheer level of pig ignorant racists and knuckle draggers prepared to 'protest' in the name of these horrific crimes. I've alluded to it elsewhere but arresting people on the night was not practicable for several reasons-and that means when identifed suspects will be arrested in slow time.
Also, if somebody rocks up to a potential riot-you dont always get to make the decision when you go home. You've pretty much forfeited that.