Great thread, I really want to see that doco.
I remember visiting relatives in South Shields in the mid to late 70's, they used to live around the Hill area, which was pretty rough (there was a huge Doc Martin boot spray painted on a wall with a square around it and 'Incase of Emergency Break Glass' written underneath

I also remember the Sham Army that used to hang around the Handyside Arcade in town, was always hearing stories of my mates getting filled in by them.
I remember getting a Chelsea skinhead (fringe left on) when I was about 12 and getting my first pair of Doc Martins... I also remember when the older lads I knocked about with and went to the football with changed their style and started calling themselves Casuals - wearing Fila cagoules (early 80's) - I think they were impressed with the look after a run in with the Leeds Service Crew

You'll find similar stories of gangs all over the country, and I'm sure many similar stories. I think an important point made previously is back in those days you would often become mates with those you fought with, a mutual respect of each other - you don't get that these days, the whole respect thing has become one way only.
I'm currently in Oz and have been interested in gang culture and history here, here's a little clip of the Melbourne Sharpies from the late 60's (a sort of early proto-skinhead movement) and the Mods at the time.
Sharpies in 74'