You could try contacting Robin williamson. I know he is still performing. he plays Celtic Harp, so if you can't google and address/contact info for him I should be able to ask the Harplist for info.
I don't have the ISB album with Sleepers Awake on it, but I have a couple of others. (I'm useless at deciphering lyrics anyway, so I wouldn't be much help even if I did have the album.)