(For one actor, the failure worked out to his benefit. Being free, Ronnie Corbett -- who played 'Will Scarlet' -- was hired to be in the TV show, The Frost Report, with David Frost, and this ultimately lead to him later co-starring in his own series, which even made it to the U.S., The Two Ronnies.)
The cast album was recorded, and a CD is even available on Amazon -- though it's clearly rare and is listed for $71. (But it's a more reasonable $34 on Amazon's U.K. website. And on iTunes you can get the songs for just $8.99) I've been able to find a couple of the songs online, though. This one here, 'May a Man Be Merry?", is from what appears to be a very odd album that Lionel Bart himself recorded and is described on YouTube as his "late '60s acid breakdown LP," titled Isn't This Where I Came In? So, I'm not sure if this was the arrangement of the song that was used in the show. There's a short video elsewhere of a fellow doing an instrumental cover of the song with just an acoustic guitar, which is a significantly "gentler" rendition. I don't particularly care much for the song, though that might be because of Bart's recording. But it certainly is...well, intriguing. It also apparently got cut from the show not long before the opening. Or not. It isn't listed on the album, though is listed here in the Twang page of the Guide to Musical Theatre.