A friend (thanks Alison) just pointed me to some amazing Youtube videos by Humber College (Ontario) music student Danny Fong, sometimes with his brother David. Impressive a cappella performances with videos of him/them doing each track.
For example start here with their rendition of 'Scarborough Fair' and from there see some of the other nice ones, such as Gene Puerling's 'All the things You Are" and 'Nightingale in Berkely Square".
Apparently no Melodyne! Eat your heart out Anders!!
All the best, Paul.