Hullo all. Insulators, eh? One of my topics!
Most insulator collectors are only interested in the glass (or porcelain) and so most insulators are sold
sans hardware. In the US, they are just threaded onto the metal/wood pins so this is no big deal, you just unscrew them; in the early "threadless" years, they were cemented/glued onto plain wooden pins. Very very rare to find original threadless pins these days, and if you found an original insulator/pain combination, you would never ever try to separate them. They can only be original once!
For "foreign" (non-US) insulators, often they are cemented on, and removing the pins is a huge pain. I had thought the OZ pieces were threaded also, just with a different (metric) pitch. Is that not so? At any rate, I can tell you that in the US, Lou Hall is the main collector of insulator hardware-- he collects mostly any hardware that insulators were attached to, instead of the insulators themselves. Not sure if he's into "foreign" or not. Here is one of his hardware displays at the 2005 National show:
Most collectors will not want them with the hardware.
BUT, some definitely do, me included, and the original, matching hardware is often much rarer than the insulator itself.
Since they can only be original once, I would keep them in original condition, and pass them along as-is, or at least give the option. If the buyer wishes to remove them from the hardware, they may do it themselves (there are write-ups about how). It's a lot of work sawing and extricating the cement, however. You may want to try removing the hardware from one (duplicate?) just to see how much work would be involved. There's always the chance of damaging the insulators (or yourself!) during the operation, so be warned.
Two of my most prized "foreign" (French) insulators are on the hardware, an asymmetrical pair like in this postcard (but in a nice green glass):

Look, they are surrendering, ha ha!
I'd be interested in seeing pictures of your OZ pieces. Presumably they are AGEE, or AGM or CCG. "AGEE" is a bit funny: the company was Australian Glass, whose abbreviation AG sounds like you've just taken a crossbow bolt to the neck, so they emboss it AGEE on the glass so you will know how to pronounce it properly! You can find
a history of Australian insulators here.
Cheers...
--ian