The £20 x 80 Seat regional events are events in there own right, but they are also satelites to the national events.
The points that you win in the regional events count towards the final standing at the end of the season, and points are awarded to the top 9 places. Also, if you finish in the top 10% of runners you get a seat in the National Event.
May be a bit much to take in, or I haven"t explained it well, but that is it in a nutshell.