What to do with Acrylic Platter?

I have just made a couple of trips to the machine shop and am a bit disappointed.I had an acrylic Rega Platter machined and increased its depth from 10mm to 15mm.So it is supposed to be 295mm across,hole 20mm and depth 15mm.They could'nt get the hole right on 2 attempts and I now have 2 platters,one with a 20.5mm hole and one with a 21mm hole.They are an upgrade to the glass,and I am using a small piece of double-sided soft tape inside the hole to get a snug fit on to the wider part of the Rega spindle.This works ok but do you have better suggestions?Stefanl