it is probably safe to say that, prior to 1066, the church of the British Isles was Orthodox, and the Normans brought the effects of the Great Schism to British soil. As such, it is probably proper to regard King Harold II as an Orthodox Christian.
Is there any truth to this idea?
In short answer, no in the sense of Eastern Christianity.
I argued against some concrete points of such claims in How true is it that England was briefly Orthodox before the Norman Invasion?
It is worth noting the the wiki OP linked has only one literature on Christianity in Late Anglo-Saxon England in the reference list, and the book in question is also problematic one.