The activities of the mediaeval church have left the records of English folk music and song limited, so the richness of the English heritage is indeed limited in comparison with Scottish and Irish.

How so? For one thing "the activities of the mediaeval church" in Scotland and Ireland were much the same as in England or in other parts of Europe. For another it's highly questionable whether much of the living musical heritage in any of those countries dates back half a millennium to mediaeval times.