SteveP - maybe just to add a bit more "gravity" to your letter, you really ought to include the full VINs, along with the names/addresses/reg numbers of registered keepers.
And for future reference, you could actually sort them by VIN order, and actually check when they were built.
Good point T_T, but as some people are a little relucant anyway to send some details to a man they have just meet on the t'internet as it is so asking for all that seamed a bit much.
OK, I can understand. But you have been here for some time, and have a reasonably hefty post count. It isn't as though you have just registered and make up 10 posts for using the pm service. Have you got similar post counts on the other sites such as uk-mkivs and the likes? Or have you linked back to this thread?
At the end of the day, we all need to be able to "gauge" when to trust others, and if some choose not to, and don't get their plaques, then it could be their loss.

Regarding you point on the "overbuild" is there any way to get offical copies of VW press releases?, as I have seen lots of stories on the net about VW appologing for the 800 additional cars at the time when the Pirelli edition was confirmed earlier this year, all calling it something like a "honest mistake".
I suppose the most important bits of written info would be the official sales brochures. I am looking at "Issue: 1 November 2006, PVW156GMK", and it makes no claims that the Ed30 is limited in any way. However, it is fairly common for VW to release maybe three brochures per year, along with the corresponding price lists, and these can change fundamental details. If the said brochure was given by the salesman during the pre-sale negociations, then the said brochure then forms part of the "contract of sale", and anything said in the brochure is deemed to be part of the agreed specification, UNLESS it is officially notified in writing at the time of signing the contract, or up to date of delivery.
Another option would be to write to Volkswagen Driver magazine, who are arguably the most respected Volkswagen mag out there - and they are alleged to work very closely with Volkswagen UK and Volkswagen Germany.
Avoid virtually all internet sites like the plague (as a direct reference). Virtually all the US-based ones, particularly AudiWorld.com, VWvortex.com and Fortitude.com have repeatedly been found to publish factually incorrect info.
For the official VW press site, try
www.VolkswagenMediaServices.com - anyone can have free access to view, but you need to be officially registered with them before being able to download press packs, high res images, and pdfs of general articles. If you do find anything, let me know, because I have press registration to virtually all the Volkswagen Group brand websites, and I'll download anything you find.
HTH