This is the beautiful example of exactly what I meant. This gentleman believes that the force used against him was unlawful. So what has he done? He has gone to the Independent Office for Police Conduct, who will either do a full investigation themselves, or order that it is done locally by the force (with the caveat that he can always appeal back to them if he disagrees with the outcome).
After too many horrendous incidents, we have many checks and balances over police power in this country. Do police get it wrong? Yes, and frequently. Should they be brought to account? Of course. But police do a difficult and frightening job (I could hear the fear in that officer's voice) and, having observed police officers in other jurisdictions, we really do not know how good we have it.
I am not a police officer, by the way.