Moley - the answer will depend on who your target audience is - what type of students are you trying to attract ? - if you want to attract Kids then film segments of the "Three K's" from kids classes - if it's teenage males emphasise the "action/sport/kumite/breaking" stuff - if it's young women perhaps include some SD against bigger males etc. - if it's older students then have the "decrepits " (lloydie and yourself perhaps?

) beating the cr@p out of the "young alpha males" (Alex perhaps?) etc. etc. and if it's ALL of these groups then shoot several and come up with a way of expsoing the target group to the respective demo shoot.
Just some thoughts.

...and regarding the best angle for shooting I think that shooting slightly upwards from a lower position works best for general "action" shots - as opposed to "the referees view" - if that makes sense. For breaking stuff the "best" viewpoint will depend on the "strike" direction to an extent but you would normally (IMO) start off "zoomed out" and then zoom in and reorientate to capture the break from your preferred viewpoint.
You can also capture breals from diffenet close up viewpoints/angles as well.
I'd suggest using more than one camera as well to capture the action simultaneously from different viewpoints - as this allows you more creative options" when editing - e.g. "picture in picture" for the break with the close up/other-angle either in a box on-screen or as a video overlay etc.
Jim