Don't know what specific event this was but most of the windsurfing shops organised races at times. Yes, there were several windsurfing shops in SA in the 1980s. As this event is at Glenelg it may have been run by "Windsurfing Glenelg" which was on the corner of Colley Tce and Anzac Highway (now an apartment block). My first board and gear came from Windsurfing Glenelg. Glasscraft Marine also organised a lot of events and gear test days.