But was it doctrinally different from Chalcedonian Christianity to justify its own colour on the map. Wikipedia suggests no, which chimes with my understanding: some local minor differences in practice, but nothing like the Christological disputes that caused the rift with the Church of the East, nor like the row over papal supremacy etc. that led to the Great Schism between Roman Catholicism and Eastern Orthodoxy.
That is correct afaik, though there were serious disputes in Anglo Saxon Britain about these and other issues (mostly about 'leadership' of the church as in any human organization). I'm not sure if it warrants another color, etc though per this video.