Just me, but I think if you try and sell small amounts on the forum, you'll build up a reputation as being reliable. I (personally) wouldn't sell to a refiner as they'll a) pay you way less than spot (they need to make a profit), and b) technically it's illegal to melt down Australian currency, and the only non-legal tender Australian currency is the holey dollar and the dump. You are far better (IMO) to sell 100g here, and 100g there and slowly build up a reputation as a reliable and trusted seller.
No, no-one will come after you if you do decide to melt the coins, but really if you do, you are doing yourself a disservice (IMO).
The other option is to take them to your LCS and see what they'll offer you (for the pre-65 stuff [and assuming they're not worn to the point of being slicks], don't accept less than 5% below spot, and for the post-65 stuff, don't accept less than 15% below spot). It might take a bit of work, but 5%/15% below spot should be your absolute lowest price point for selling them.
Again, all subjective and just my opinion. YMMV.