Thanks for the feedback and ideas. I may well have to buy in bulk and then have it cut. I have emailed TrueVue to ask whether we can laser-cut the glass sheets or if that will cause separation of the AR coating (I know we cannot laser cut the non-glare acrylic, but they don't say either way about the reflection-free glass).
The UltraVue prices look good, if a local supplier here will do the same price. Water white, reflection-free, 98%+ light transmission, sounds darn well ideal as long as it is strong enough at 2mm. I do think any water white reflection-free (AR) glass should do the trick.
This will be going into a standard Dan & Rob kit build... Once the thing is assembled and working with cheapo glass, and all working as it should, then I'll see about replacing with some water white AR. 6-8 weeks is a good guess on timeline, so I'll post back here then with results.