The basic track version, that is from "The Geese & the Ghost".
I was trying to figure out how many guitars are playing. Sounded like a dozen to my ears, but I wrote Anthony Philips' website to ask & got this reply:

"Thanks for your message. In answer to your question, there are no overdubs on the basic track version of ‘Silver Song’ – it’s just played on two 12-string guitars by Ant and Mike Rutherford."

!!!
*Only* 2 and *no* overdubs?? Well, guess it's true coming from the horse's mouth. I'd post it here for listening, but I only saw the finished version on Youtube.