Throwing a completely new spanner in the works, is it worth pointing out that East anglia is full of Dutch? Vermuyden and all that lot, digging bloody great drains etc? Is het Wild Rover een oude Nederlaanse liedtje?

There's a fabulous record by Swedish Trio "Frifot" that has a song on it that is obviously related to the English ballad "Long Lankin". etc etc.

Brian, your "Swansea Town" I've heard as

"Her hair it was as black as soot/ in bunches hanging down,/ I've searched the world all over/ But her equal can't be found/ She's the Blooming Rose of London/ And the Lass of Canning Town."

The point is that this sort of transmission of music happens all the time. If someone hears a good tune, they'll learn it. To whit: all the English players of Irish music. This is not a new thing, and while it makes a load of problems for Ethnomusicologists, it's basically a good thing.

Cheers,

Jon