The related thread "Willy O'Winsbury as done by Pentangle?" includes a link to a midi tune, and a couple of chord versions that may help. They don't fit the tune in my head though - which is a version by Leonard and Squires from "Broken Down Gentlemen" - and If there's a version to beat this (highlighted by a gorgeous fiddle solo by "Squigsy") then I'd love to hear it!