Hi Syph, thanks.
So there is a round glass element that pops out of a clear plastic frame? I didn't realise that, I thought perhaps new manufacturing techniques allowed them to cut and shape the whole tool out of a single piece of toughened glass.
Here in Aus it would take me a week to find 3 tools, and they'll all be old stock, guaranteed. I also don't think Amazon will ship knives, but I'll try.
It's a shame there's no easy way to tell the difference. Sounds like I'll just have to roll the dice and order from busy eBay sellers!