NSW Lent Items Being Sold Without Permission?

I lent a small hifi system I own to a local club (I was until recently on Board of Directors). Some of the speakers with this were not being used at the time, so they were put away until needed. Last week I went in search for a couple of these speakers as I was going to use them for a party I was having. But, they could not be found... When asked where they were, all denied knowing or seeing them.

This afternoon, I came across the same speakers being sold at my local Tender Centre. I can't be sure they are mine, but they are the exact same ones that are missing.

Where do I stand, and what is the best course of action I can take to see if they are mine, and if so get them back?