21d consonant with transaction involving set of books (6) I have - EN - AL I think it may be DENTAL which fits the cryptic clue - DE(NT)AL, but not sure about dental = consonant.
Two to get - help please! 29a Fair woman maybe one's joined early (5) I S O - - (Could it be Isold?) 23d Slippery old Scots held up by English flight? (5) - L I - E