Found this terrific source of information today:
http://www.magnoliasociety.org/I'm finishing off merging the Sherwood plants into the Master Database then will be back on our Winter lessons!
Sherwood have a large collection of Magnolias and have sent me good photos on CD. They will be in your next copy of the Master Database and a new WPG like this:
http://www.ideasforgardens.net/Sherwood/Azaleas/