I think the >>cross-pollination of ideas<< was achieved by the walkabout each mechanic made. This was the conduit for the transfer of technology & more than likely how pattern welded tubes made their central migration, along with spoils of war. We know that many of the Continental mechanics passed thru the Little British Isles, but I haven't seen any info for vice - versa.

Cheers,

Raimey
rse