Mick,
To be honest I don't remember Nic Jones from that period at all. I'm pretty certain he was not booked at our club at the Bluebell, Hull, not until about 1972. I'd heard 'Calico' being sung by Dransfield or Sobell long before this, and I must have heard it frequently for me to be able to sing the chorus now after 40 odd years. They may have got it from Nic but I later assumed they'd picked it up off Harry Boardman. If that's the case he probably got it off a broadside. I know Harry and Roy Palmer included a broadside printing of it in one of those street literature folders they published in the 70s.