Brian, is there anything you DON'T have stashed somewhere? What I'd give to wander around that Aladdins cave of yours ... That would be great if you could find them, thanks!
Peter, I did flame-polish the outside to good effect, but I can't get the nozzle inside the drill-hole ... Tried pointing the flame into the hole but just melted the rim!
I don't know if you can get a cheap blowtorch with a very fine nozzle that would fit into an 11.25mm drill hole, but I suspect the flame would go out for lack of oxygen inside a closed-end hole? 
I'll read the article with interest, thanks Pete! Don't know if this is the same stuff as water clear PR, mate - probably, because it is cast acrylic, but I could be way off? 