G'Day BW,
Mate the nearest offshore reef from Reddie Bay would be off N Straddie, around the group or 7's. You will need to cross the South Passage Bar, not sure on the latest conditions, but needs to be treated with caution. Good idea to do a Bill Coreton bar crossing course, as this is the bar he uses and you won't find a better teacher.
Better off using Raby bay to launch from with a quick trip across the top of Peel and up the Rainbow channel will get you to the bar, or alternatively just zip out thru the Small ships channel and then onto the Rous channel. (there're all in Brownies B to B)
Cheers,
Tony 8)