This could have been handled very easily. Fire so much tear gas at them they cant see or breathe.
Follow up with Baton charges and or volley of Baton round.
After that when they wake up in hospital with broken and smashed limbs, I can tell you they wont be saying they have no fear of the police or rule of law.
I very much doubt you would see any of them doing it again either.
Unfortunately due to our pc society the police have been castrated in this country. They have neither the support of the willpower to police like this anymore which is why we find ourselves in this situation.
You will note that the copy cat riots did not occur in Scotland, Wales, the North East of even Northern Ireland due to the police in these regions still having the fear and respect of the community overall.
If the same thing was happening in Germany, France, Holland, Spain, Italy, America etc I can gurantee the response would be similar to that which I suggested.