As I mentioned earlier, the tune (which varies in details rather than essentials) is known in a number of other parts of the country (including Winster in Derbyshire, a few miles from where I live), usually associated with the Morris. Whether or not it was brought to Derbyshire by Cornish miners moving up there to work in the lead-mining industry is a matter of conjecture. Hal an Tow, of course, is a different song entirely.