Possible Clues:

• Volume of tax return accepted by firm starting with nothing
• 6 x 9-inch page size
• Eightfold in volume
• Size of a book, pages are made by folding a sheet of paper three times to form eight leaves (6)
• An eight-leaved book or page
• 50 following the torn coat in book form
• A size of book page
• By the sound of it, ate the leaves of this in volume
• Folding leaves eight
• 8vo