Ian, you do a great job of educating how slowly and painfully things can move when selling to the enterprise. A keyword for selling to the enterprise is patience. People inside the enterprise themselves get frustrated with how slow things go and are grateful for vendors who understand and work with this.
Re RFP: a good technique is to ask the contact at the enterprise how many people have received the RFP. Often the answer tells you straight away to not bother.
Who did your proofreading? For a self-published, free ebook, the copy was surprisingly free of typos. (Although page 29: "If there isn’t,, "). If the proofreader is an independent freelancer, could you please PM their contact details?
Are you trying to sell anything in particular to the readers of the ebook? If so, it wasn't clear to me. That may be your intention - subtlety does seem to be in short-supply amongst people conducting online marketing.