A general decrease in ozone concentration has been observed everywhere in the stratosphere, on the order of 5%, but polar conditions are such that ozone concentration is dramatically reduced in September-October of each year.
Without having looked, does this site explain why this reduction occurs in the South Pole (not near CFC sources)rather than the North (where there are lot's of them)?
Yes. In Part 3, concentrate on the section entitled "The Special Features of Polar Meteorology" (even though the figure is blurry). The bottom has a nice quick summary.