There's a little bit about The Cure, literally a minute or so, with Ralph Sall (the album's producer) talking about the band's contribution and showing clips from the Hello Goodbye video.
There really isn't much information sadly, many of the other artists actually appear themselves discussing their song. Basically Sall said he called Robert himself to ask them to take part, that. Robert is a huge and very knowledgeable Beatles fan and Robert chose Hello Goodbye himself.
May be worth a watch for anyone interested in the other songs." (Thanks Dave Ace)