Well just a scan back through the archives on GC and the number of hip issues that have come up might change a thinking mind about the prevelance of HD in Pembrokes. As I'm sure you realize even excellent to excellent parents can end up with dysplastic get. The US is the leader in screening for HD, not many other countries do.
Peggy was right in her interpretation of what I meant by this forum not being the best resource for the questions you are asking. Those with the background to provide the info you are looking for are a minority and a very small one at that. I can understand wanting to keep a bit anonymous though. You might also want to look into Corgi-L
The OFFICIAL Corgi-L Home Page! which is the oldest general corgi discussion list around. There are many show people on there, but it's focus is general discussion.
There is a DNA marker for vWD, although reports coming in now are not so certain that the test is as accurate as it was believed to be initially. Unfortunately this is showing up during c-sections. Pembrokes are not the easiest of whelpers and require a lot of assistance (and c-sections), although our friend from NZ will dispute this fact, he's not spent any time in a whelping box either.
Another health issue to research is degenerative myleopathy. Seems to be an increase in Pembrokes showing up with it, or at least they are more visible or we hear more about it today. Could be better communications via the internet, or being more openly talked about by breeders, better diagnosis or the CorgiAid cart program bringing it out into the open more or all of the above.
Debbie