You can tell just from that clip that the bloke is most likely one of those absolute jobsworths.
Really? I know there are a lot of things being read into a short clip (me included), but can you really tell that the bloke is an "absolute jobsworth"?!
What you can see is that after he grabs him, the bike gets underneath their feet, causing them to overbalance and hit the deck. I can't see any aggression, any big attempt to throw the kid over - nothing to suggest the officer was out of control.
It certainly doesn't look like a big enough impact to cause anything more than a bruise and/or graze but obviously it's inconclusive on that front. What I do know is that if the kid had been injured in any serious way, it would be plastered all over the press.
It's a storm in a teacup and no mistake.