Wendrich Art House is made by two adepts of the Golden Dawn, Harry and Nicola Wendrich. They are talented painters and they have transmitted their talent and skills on art to create a tarot deck for the Golden Dawn practitioners, paintings inspired by the Tree of Life and the Hermetic Kabalah and Runes. They have also written a book to accompany the Golden Dawn Temple Tarot, which is based on the tradition of the Golden Dawn and their meditative experiences.
On their website, you will also find a study section for the Golden Dawn Temple Tarot.
You can see a review of their products here.
Theurgy and Philosophy are two different methods which lead to the union with God.