eastern and orthodox christianity at soas
Dear John Mark,
Yes, finding relevant material is difficult, not only because of their rarity in public libraries, but because of their exorbitant prices if available for sale.
I know two of the books you mention:
A. Atiya's History of Eastern Christianity is available from the Kent County Library at Springfield, Maidstone, Kent, and is worth reading but, unfortunately, although the author is a good authority on the Coptic Church, he is less knowledgeable on other Ortiental Orthodox Churches;
J. Trimingham's Christianity amngst the Arabs in pre-Islamic Times is also available from the Kent County Library, but I would not recommend it, the author displaying rather breathtaking ignorance and anti-Christian bias, regarding everything the Fathers said as being questionable.
Good luck with your studies,