Reword main intro to be more factually accurate

Facts that were wrong:

 * SR is held at the University of Southampton:
   The competition is in Newbury this year, and kickstarts are at a
   variety of places (listing them in the intro would be silly).

 * Run by students at Soton and Bristol
   Several of our organisers and volunteers are not at Soton or
   Bristol.

I think there's more work to be done here later, but this patch makes
the intro correct at least.

Change-Id: Iee55fb194a59c461fcb3d0ddfae9f44523b40cce