Many thanks for clearing all that up, John.

IanC's earlier claim for the North West of England was always based on false ideas. The reason why many Irish songs were printed by northern printers is that they usually came in via Liverpool either in already printed form or in oral tradition. Many other examples as I'm sure you can attest.

You can actually follow the trail of evolution in England of 'The Strands of Magilligan' as it morphed into 'The Streams of Lovely Nancy' by the time it reached southern England.