To locate collectors of the works of the artist Horatio Couldrey. Also any information about his works.

It's actually Couldery, not Couldrey. Info on him and his prints abound on the internet:
http://www.google.com/search?num=100&hl=en&safe=off&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=%22Horatio+Couldery%22&spell=1
That should give you a good start.