It's too bad Rega keeps sending out turntables with platters that wobble. I'd call your dealer and see if they can work with Rega (sound organization) to send you a replacement subplatter before exchanging out the whole table. I'd also suggest taking the glass platter off and look at the subplatter spin on it's own. If you don't see any vertical movement in the subplatter the subplatter is fine and it's probably the glass platter.
Here's a video showing the new subplatter I received from Rega wobble was still there.http://www.youtube.com/watch?v=zRsvIIN7aQw
Here's a video showing a new glass platter they finally sent me.http://www.youtube.com/watch?v=t1aAYDy145c
so again if you don't see any movement in the subplatter with out the glass platter sitting on it, I'd push hard to have them send out a new glass platter to you.
Video really helps things when talking about these issues. I took my digital camera set to video obviously and placed the camera on the plinth making sure the lens was set for macro so it would focus close up. From that angle you can really see what's happening with the wobble. I can't tell you right now if 1mm of wobble is that much I'd have to see it, but since you've noticed the wobble I'd assume it's not acceptable. Who wants to look at a platter wobble while listening to records?
Rega P3-24 | Groovetracer Reference Sub-Platter | Rega Stock Belt | Shure M97XE w/ Jico Needle | Rega Brio-R | Pioneer SP-FS51-LR Speakers (Andrew Jones)