Hey Steve, thanks also for the comment on the blog, Nathalie is always thrilled to get these
Sorry I lost track of the thread and didn't reply back with the link myself.
The beach at Secret Harbour was actually very nice in the middle area, the rocky part was likely near the dive shop (also lots of urchins there too, so look out).
We never had trouble getting lounge chairs and an umbrella and they also had some paddle boards/kayaks .. we got some vouchers with our dive package, so free.
The dive shop also did snorkel trips (they had a separate boat for those).
You can also do shore dives off the beach (on either side).
Enjoy your trip.