Buddhist Education Foundation (UK): Foundation aiming to promote Buddhist education in the U.K. Produces suitable textbooks on Buddhism.
Parallax Press: Publishes books by Thich Nhat Hanh and others. From the website - "Parallax Press is a project of the Community of Mindful Living, dedicated to publishing books and tapes on socially engaged Buddhism."
Shambhala Publications: Books on Buddhism. A wide diversity of works.
Tharpa Publications: Publisher of Buddhist books by Geshe Kelsang Gyatso about basic Buddhism, meditation and the Mahayana and Vajrayana paths.