I am familiar with the United Orpington Club, which is the current recognized foremost club of orpington breeders, and am proud to be a member of the club. It is an excellent club, well established, and I encourage all who are interested in the breed to join. It is a very active club, with great members that I have found to be very helpful and encouraging, even though I do not show. As fewer than 1% of poultry keepers show, that is important to me. The club is "dedicated to
all Orpingtons, Large Fowl and Bantam, and to the breeders of this fine fowl." Members receive a quarterly newsletter, "All Orp," an annual breeder's list, and membership list. The newsletter is just fabulous, too! I always look forward to it. You will find, on the club website:
History
Standard
Breeding/Exhibition Tips
Photo Gallery
UOC Officers
Informational Articles
Member Classifieds
Constitution/ By-laws
and more!
The club website is here:
http://www.unitedorpingtonclub.com/
I suggest to the OP to contact officers and members of the club, and I am quite sure they could be helpful with answering some of your questions, too, as they have members with both Imported English Orps and APA standard Orps. Heck, many enjoy them both!