Just as an update, I received the pdf today from 1dollarscan and I'm delighted with the results. The original size of the pdf was 330 mb
but I managed to reduce it to 7mb after running it through Finereader and Calibre. I just have a bit of clean up work to do in Sigil and then it will be ready to send to my friend, who is still gnawing his teeth at the thought of scanning 740 pages
Thanks again for everyone's help with this.