Sandy Denny sings White Dress, which Swarb wrote for her, very neatly. Dave Mattacks plays drums on this song. It was released on Fairport Convention's album Rising for the Moon and as a single White Dress / Tears. It was later included in the cassette The Attic Tracks Vol. 1, on the Fairport Convention compilations Meet on the Ledge: The Classic Years 1967-1975 and Fiddlestix - The Best of Fairport 1972-1984, and on the 5CD Fledg'ling Sandy Denny anthology A Boxful of Treasures.
There is a short clip on YouTube of Sandy Denny singing White Dress at the London Weekend Show in 1975:
Vikki Clayton covered White Dress on It Suits Me Well.
Addendum by Paul Wright: “Another version of White Dress occurs on Ralph McTell's album Slide Away the Screen (1979) with Ralph McTell, vocals & acoustic guitar; Simon Nicol, acoustic guitar; Jerry Donahue, electric guitar; Martin Jenner, steel guitar; John Mealing, electric piano; John Kirby, piano; Dave Pegg, bass; Dave Mattacks, drums. The verses were rewritten from a man's viewpoint and credited to McTell/Swarbrick. This version was also played live at Broughton Castle by Fairport Convention in 1981.” A further recording of Ralph McTell singing White Dress accompanied by Dave Swarbrick from the 1992 BBC Ralph McTell Show is on the Dave Swarbrick anthology Swarb!.
Sorry, I can't show the lyrics here as I don't have the copyright owners' permission to publish them. But please feel free and ask me to send you the song's lyrics.