Gosh -- another great thread I missed first time around!
I only know what I heard when it came out, and a bit more in Ronnie Lane's documentary (
The Passing Show: Life & Music of Ronnie Lane), which jives with livewithme's explanation above -- i.e., Ronnie Lane needed money as his MS set in, Pete Townshend didn't want to lend him money but started asking around who'd want to be part of making an album with him and Ronnie Lane, the proceeds to go to Ronnie's medical treatments. Glynn Johns in the producer, btw.
In the
remastered Rough Mix there's a booklet and DVD about the making of the album (as well as 3 de-vaulted songs from those session - sound familiar?
) I just added this re-release to my Wish List on amazon. If I ever get it, I'll report back here if it says how Charlie and Stu came to be involved with Rough Mix.