I'm confused as to how it's happened. I was convinced I dropped it in a cache on the South Coast nearly a year ago, and unfortunately hadn't been seen since then. Then last weekend, I needed a screwdriver, so I pulled out the tools kept with the spare tyre, and lo and behold, Spike Jr was hiding. So I can only assume I failed to drop it off as I intended and when I threw my stuff into my boot, Spike made a run for it and made it's way to the spare tyre.
So I'll apologise to Spike Jr and his owners, and I've put him in Monaro TB Tank hoping that he'll speedily be on his way again.