Having just watched the CCTV I cannot see anything which warranted that abuse. Yes he is in the army (they dont know that, I dont think) to them he is just another p!ssed up reveller, but he's in the REME (not a fighting arm)
A generalisation made here is that everyone in the army is a trained killer. Yes we are allowed to use lethal force if required, but I myself am trained to repair human beings on the frontline and defend myself if attacked just like the rest of us in the AMS. I am not taught, like some beleive, how to snap someone's leg with my thigh nor do I know how to perform the Vulcan sleep grip.
I dont condone soldiers making a nuisance while out on the p!ss, in fact it often gives me more work, but in this picture I cannot see any reason for the force used. In my view they are not respresentative of the police force I know, one which deserves respect for the work they do. That officer at the head should be punished, that was not 'reasonable force' there are much better techniques you could use in that scenario. That just seemed an easy excuse for gratuitous violence.