Has there been any change to the route taken by aircraft taking off to the South from Sydney Kingsford Smith Airport; if so, (a) what have those changes been, and (b) what has been the reason for those changes.

Yes. Airservices Australia has advised that -

(a) and (b) There have been a number of minor modifications to the route taken by aircraft departing to the south. The first was in December 1998 when a new DVOR (navigation aid) was installed and commissioned. The new positioning of this navigation aid moved the southerly departure flight paths closer to the coast. To rectify this, the DEENA Standard Instrument Departure (SID) was introduced in June 2000 which moved the flight track back to a position similar to that which existed prior to the new navigation aid being commissioned. In April 2001, a change was made so that those aircraft departing the main runway and tracking via Wollongong would turn out to sea at 13.3 nautical miles rather than at 14.9 nautical miles. These modifications were undertaken in consultation with the community and industry through the Long Term Operating Plan Implementation and Monitoring Committee. The DEENA SID was introduced to assist in reducing aircraft noise over the Kurnell/Cronulla/Bundeena area.